National Football League The National Football League ( NFL ) is the highest level of professional American football in the United States . It was formed by eleven teams in 1920 as the American Professional Football Association , with the league changing its name to the National Football League in 1922 . The league currently consists of thirty - two teams from the United States . The league is divided evenly into two conferences — the American Football Conference ( AFC ) and National Football Conference ( NFC ) , and each conference has four divisions that have four teams each , for a total of 16 teams in each conference . The NFL is an unincorporated 501 ( c ) | 501 ( c ) ( 6 ) association , a federal nonprofit designation for tax - exempt professional football leagues , comprising its 32 teams . The NFL is by far the most attended domestic sports league in the world by average attendance per game , with 67 , 509 fans per game in 2009 . The regular season is a seventeen - week schedule during which each team plays sixteen games and has one bye week . The season currently starts on the Thursday night in the first full week of September ( the Thursday after Labor Day ) and runs weekly to late December or early January . At the end of each regular season , six teams from each conference ( at least one from each division ) play in the NFL playoffs , a twelve - team single - elimination tournament that culminates with the championship game , known as the Super Bowl . This game is held at a pre - selected site which is usually a city that hosts an NFL team . History . In 1920 representatives of several professional American football leagues and independent teams founded the American Professional Football Conference , soon renamed the National Football League . The first official championship game was held in 1933 . By 1958 , when that season ' s NFL championship game became known as " The Greatest Game Ever Played " , the NFL was on its way to becoming one of the most popular sports leagues in the United States . The merger with the American Football League , agreed to in 1966 and completed in 1970 , greatly expanded the league and created the Super Bowl , which has become the most - watched annual sporting event in the United States . Season structure . Since 2002 , the NFL season features the following schedule : Traditionally , American high school football games are played on Friday , American college football games are played on Saturday , and most NFL games are played on Sunday . Because the NFL season is longer than the college football season , the NFL schedules Saturday games and Saturday playoff games outside the college football season . The ABC Television network added Monday Night Football in 1970 , and Thursday night NFL games were added in the 1980s . Exhibition season . Following mini - camps in the spring and officially recognized training camp in July – August , NFL teams typically play four exhibition game s from early August through early September . Each team hosts two games of the four . The exhibition season begins with the Pro Football Hall of Fame Game , so those two teams play five exhibition games each . Historically , the American Bowl ( s ) were played prior to the NFL scheduling regular season games abroad and those teams faced this similar predicament . The games are useful for new players who are not used to playing in front of very large crowds . Management often uses the games to evaluate newly signed players . Veteran starters will generally play only for about a quarter of each game to minimize the risk of injury . Several lawsuits have been brought by fans , against the policy of including exhibition games in season - ticket packages at regular season prices , but none have so far been very successful . Regular season . Following the preseason , each of the thirty - two teams embark on a seventeen - week , sixteen - game schedule , with the extra week consisting of a bye to allow teams a rest sometime in the middle of the season ( and also to increase television coverage ) . The regular season currently begins the Thursday evening after Labor Day with a primetime " Kickoff Game " ( NBC currently holds broadcast rights for that game ) . According to the current scheduling structure , the earliest the season could begin is September 4 ( as it was in the 2008 season ) , while the latest would be September 10 ( as it was in the 2009 season , due to September 1 falling on a Tuesday ) . The league uses a scheduling formula to pre - determine which teams plays whom during a given season . Under the current formula since 2002 , each of the thirty - two teams ' respective 16 - game schedule consists for the following : Although this scheduling formula determines each of the thirty - two teams ' respective opponents , the league usually does not release the final regular schedule with specific dates and times until the spring ; the NFL needs several months to coordinate the entire season schedule so that , among other reasons , games are worked around various scheduling conflicts , and that it helps maximize TV ratings . Playoffs . The season concludes with a twelve - team tournament used to determine the teams to play in the Super Bowl . The tournament brackets are made up of six teams from each of the league ' s two conferences , the American Football Conference ( AFC ) and the National Football Conference ( NFC ) , following the end of the 16 - game regular season : In each conference , the # 3 and # 6 seeded teams , and the # 4 and # 5 seeds , face each other during the first round of the playoffs , dubbed the Wild Card Playoffs ( the league in recent years has also used the term Wild Card Weekend ) . The # 1 and # 2 seeds from each conference receive a " bye " in the first round , which entitles these teams to automatically advance to the second round , the Divisional Playoff games , to face the winning teams from the first round . In round two , the # 1 seeded team always plays the lowest surviving seed in their conference . And in any given playoff game , whoever has the higher seed gets the home field advantage ( i . e . the game is held at the higher seed ' s home field ) . The two surviving teams from the Divisional Playoff games meet in Conference Championship games , with the winners of those contests going on to face one another in the Super Bowl in a game located at a neutral venue that is usually either indoors or in a warm - weather locale . The designated " home team " alternates year to year between the conferences . In Super Bowl XLIV , the AFC Champion was the " home " team . So , therefore , in Super Bowl XLV , the NFC Champion will be the " home " team . The NFL is the only one out of the four major professional sports leagues in the United States to use a single - elimination tournament in its playoffs ; Major League Baseball , the National Basketball Association and the National Hockey League all use a " best - of " format instead . Pro Bowl . The Pro Bowl , the league ' s all - star game , has been traditionally held on the weekend after the Super Bowl . The game was played at various venues before being held at Aloha Stadium in Honolulu , Hawaii for 30 consecutive seasons from 1980 to 2009 . However , the 2010 Pro Bowl was played at Sun Life Stadium , the home stadium of the Miami Dolphins and host site of Super Bowl XLIV , on January 31 , the first time ever that the Pro Bowl was played " before " the championship game . The 2011 and 2012 games will return to Honolulu , though the 2011 game will still be played before the Super Bowl . Calendar . Though the NFL only plays in the late summer , fall , and early winter , the extended offseason often is an event in itself , with the draft , free agency signings , and the announcement of schedules keeping the NFL in the spotlight even during the spring , when virtually no on - field activity is taking place . A typical calendar of league events is as follows , with the dates listed being those for the 2010 NFL season : Teams . Current NFL teams . The NFL consists of thirty - two clubs . Each club is allowed a maximum of fifty - three players on their roster , but they may only dress forty - five to play each week during the regular season . Reflecting the population distribution of the United States as a whole , most teams are in the eastern half of the country ; seventeen teams are in the Eastern Time Zone and nine others in the Central Time Zone . Most major metropolitan areas in the United States have an NFL franchise , although Los Angeles , the second - largest metropolitan area in the country , has not hosted an NFL team since 1994 . The Rams and the Raiders called the Los Angeles area home from 1946 – 1994 and 1982 – 1994 respectively . In 2005 , some Saints games were played in San Antonio and Baton Rouge because of Hurricane Katrina . Unlike Major League Baseball , Major League Soccer , the National Basketball Association and the National Hockey League , the league has no full - time teams in Canada , although the Buffalo Bills play one game per year in Toronto . Also , there is talk of possibly bringing the NFL to Toronto , the largest city of Canada . The Dallas Cowboys are the highest valued American football franchise , valued at approximately $ 1 . 6 billion and one of the most valuable franchises in all of professional sports worldwide , currently second only to English soccer club Manchester United , which has an approximate value of $ 1 . 8 billion at current exchange rates . ( Incidentally , the majority shareholder in United , Malcolm Glazer , also owns an NFL team of his own , the Tampa Bay Buccaneers . ) Since the 2002 season , the teams have been aligned as follows : Former NFL teams . In its earliest years , the NFL was a very unstable and somewhat informal organization . Many teams entered and left the league annually . However , since the acquisition of the All - America Football Conference in 1950 , the NFL has shown remarkable stability . The last NFL team to fold was the Dallas Texans in 1952 ; its remnants were salvaged to form the expansion Baltimore Colts . Media . Television . The television rights to the NFL are the most lucrative and expensive sports broadcasting commodity in the United States . Annually , the Super Bowl often ranks as the most watched show of the year . Four of Nielsen Media Research ' s top ten programs are Super Bowls . Networks have purchased a share of the broadcasting rights to the NFL as a means of raising the entire network ' s profile . The Super Bowl is so popular annually that many companies debut elaborate commercials during the game . Under the current television contracts , which began during the 2006 season , regular season games are broadcast on five networks : CBS , Fox , NBC , ESPN , and the NFL Network . Regionally shown games are broadcast on Sundays on CBS and Fox , carrying the AFC and NFC teams respectively ( the traveling team deciding the broadcast station in the event of inter - Conference games , presumably so that each network can show games from all the stadiums ) . These games generally air at 1 : 00 p . m . ET and 4 : 05 p . m . or 4 : 15 p . m . ET . ( Due to differences between Eastern and local time , games played in the Pacific and Mountain time zones are never played in the 1 : 00pm ET time slot . ) Nationally televised games include Sunday night games ( shown on NBC ) , Monday night games ( shown on ESPN ) , the Thursday night NFL Kickoff Game ( shown on NBC ) , the annual Dallas Cowboys and Detroit Lions Thanksgiving Day games ( CBS and Fox ) , and beginning in 2006 , all Thursday and Saturday games on the NFL Network , a wholly owned subsidiary of the National Football League . Additionally , satellite broadcast company DirecTV offers NFL Sunday Ticket , a subscription based package , that allows most Sunday daytime regional games to be watched . This package is exclusive to DirecTV in the USA ; for subscribers to Dish Network , Verizon FiOS and Comcast , the NFL instead offers " RedZone , " a less expensive single channel that launched in 2009 and airs " the touchdowns and most important moments during all the Sunday afternoon games . " In Canada , NFL Sunday Ticket is available on a per - provider distribution deal on both cable and satellite . The NFL also produces programming for various networks , mainly highlight shows like " Inside the NFL " for Showtime and other historical games through its renowned NFL Films division that generally air on ESPN and NFL Network . Other NFL - produced programs include " Hard Knocks " , an HBO series detailing training camp for certain teams ; plus the animated children ' s show " RushZone : Guardians of the Core " airing on Viacom ' s Nicktoons channel . Radio . Each NFL team has its own radio network and employs its announcers . Nationally , the NFL is heard on the Westwood One Radio Network , Sports USA Radio Network , the Dial Global - Compass Media Sports Network and in Spanish on Univision Radio . Westwood One carries Sunday and Monday Night Football , all Thursday games , two Sunday afternoon contests each week , the Pro Football Hall of Fame Game , and all post - season games , including the Pro Bowl . Sports USA Radio and Dial Global - Compass each broadcast two Sunday afternoon games every Sunday during the regular season , by agreement with individual teams . Univision carries Monday Night games , select games from the New York metro area , and all playoff games . The NFL also has a contract with Sirius Satellite Radio , which provides news , analysis , commentary and game coverage for all games , as well as comprehensive coverage of the draft and off - season on its own channel , Sirius NFL Radio . Internet radio broadcasts of all NFL games are managed through FieldPass , a subscription service . Radio stations are , by rule , prohibited from streaming the games for free from their Web sites ; however , there are numerous stations that break this rule . All 32 teams , plus Westwood One and Univision , currently broadcast through FieldPass as of 2009 ; Dial Global - Compass and Sports USA do not . Internet / new media . In October 2006 the NFL announced the league would fully operate NFL . com , including the development of the technology , infrastructure and editorial content . Launching its first major redesign since 1999 in August 2007 , the site had been previously produced and hosted since 2001 by CBS SportsLine . It is estimated that the contract cost CBS $ 120 million over a five year period . Prior to CBS , ESPN . com produced and hosted the NFL site . Brian Rolapp , senior vice president of NFL digital media and media strategy : “ In a rapidly changing digital landscape , bringing NFL . com in - house provides us greater control of our valuable content and enables us to strategically build the site as a media asset . Fans can look forward to an even more entertaining , interactive and informative site built upon the expertise of the NFL and its other in - house media outlets such as NFL Network and NFL Films . ” Univision Online , Inc . , the interactive subsidiary of Univision Communications Inc . , and the NFL announced in January 2008 that they will jointly manage and operate NFLatino . com powered by Univision . com , the official U . S . Spanish - language website of the NFL . NFLatino . com is the only Spanish - language website in the United States to feature NFL video game highlights . In addition , the website includes live radio broadcasts , up - to - date stats , Hispanic player diaries , Fantasy Football and an insider ’ s view of all 32 teams . Announced in March 2009 , NFL . com received its first - ever Sports Emmy nominations , which earned recognition for its NFL . com LIVE coverage of NFL Network ’ s Thursday and Saturday Night Football ( Outstanding new approaches , coverage ) and its Anatomy of a Play , a short - form 360 - degree analysis of key plays of the week ( Outstanding new approaches , general interest ) . Beginning September 2008 , the NFL announced that it would simulcast all NBC Sunday Night Football games on NFL . com , located at nfl . com / snf . In 2007 , they had provided an Emmy - nominated " complementary live broadcast " which included a partial simulcast of the NFL Network ' s Run to the Playoffs eight game package along with expanded NFL Network analysis . The NFL offers a pay service allows fans to watch all NFL regular season , playoff , and Super Bowl games online . However , viewers within the United States cannot watch these games live . Instead , the service is updated Monday , Wednesday , and Friday . It offers full DVR functionality with the ability to watch up to four previously recorded games at once . The NFL offers a pay service for NFL fans outside United States to watch all regular season and playoff games , except for the Super Bowl , live online . This service is not available for fans within the United States or México . Player contracts and compensation . NFL players are all members of a union called the National Football League Players Association ( NFLPA ) . The NFLPA negotiates the general minimum contract for all players in the league . This contract is called the Collective Bargaining Agreement ( CBA ) , and it is the central document that governs the negotiation of individual player contracts for all of the league ' s players . The current CBA has been in place since 1993 , and was amended in 1998 and again in 2006 . The NFL has not had any labor - related work stoppages since the 1987 season , which is longer than Major League Baseball ( 1994 and beginning of 1995 seasons ) , the National Basketball Association ( 1998 - 99 season ) or the National Hockey League ( 2004 - 05 season canceled ) . The current CBA was originally scheduled to expire at the end of the 2012 season , but in 2008 the owners exercised their right to opt out of the agreement two years early . Players are tiered into three different levels with regards to their rights to negotiate for contracts : In the 2010 season , the CBA was not extended , thus changing the rules so that players don ' t become " Unrestricted Free Agents " until they have played at least six full seasons in the league . They will be " Restricted Free Agents " if they have three – five full seasons in the league . Among the items covered in the CBA are : Salaries . A player ' s salary , as defined by the CBA , includes any " compensation in money , property , investments , loans or anything else of value to which an NFL player may be awarded " excluding such benefits as insurance and pension . A salary can include an annual pay and a one - time " signing bonus " which is paid in full when the player signs his contract . For the purposes of the salary cap ( see below ) , the signing bonus is prorated over the life of the contract rather than to the year in which the signing bonus is paid . Player contracts are not guaranteed ; teams are only required to pay on the contract as long as the player remains a member of the team . If the player is cut , or quits , for any reason , the balance of the contract is voided and the player receives no further compensation . Among other things , the CBA establishes a minimum salary for its players , which is stepped - up as a player ' s years of experience increase . Players and their agents may negotiate with clubs for higher salaries , and frequently do . Salary cap . The salary cap is defined as the maximum amount that a team may spend on player compensation ( see above ) in a given season , for all of its players combined . Unlike other leagues , for example the National Basketball Association ( which permits certain exemptions ) or Major League Baseball ( which has a " soft cap " enforced by " luxury taxes " ) , the NFL has a " hard cap " : an amount no team under any circumstances may exceed . The NFL also has a so - called " hard floor " , a minimum payroll that each team is required to pay regardless of the circumstances . The NFL salary cap is calculated by the current CBA to be 59 . 5 % of the total projected league revenue for the upcoming year . This number , divided by the number of teams , determines an individual team ' s maximum salary cap . For 2008 , this was approximately $ 116 million per team . For 2009 , it increased to $ 127 million . As a result of the NFL owners opting out of the CBA two years early , in the absence of a new CBA 2010 will have no salary cap or floor . Teams and players often find creative ways to fit salaries under the salary cap . Early in the salary cap era , " signing bonuses " were used to give players a large chunk of money up front , and thus not count in the salary for the bulk of the contract . This led to a rule whereby all signing bonus are " pro - rated " equally for each year of the contract . Thus if a player receives a $ 10 million signing bonus for a five - year contract , $ 2 million per year would count against the salary cap for the life of the contract , even though the full $ 10 million was paid up front during the first year of the contract . Player contracts tend to be " back - loaded " . This means that the contract is not divided equally among the time period it covers . Instead , the player earns progressively more and more each year . For instance , a player signing a four - year deal worth $ 10 million may get paid $ 1 million the first year , $ 2 million the second year , $ 3 million the third year , and $ 4 million the fourth year . If a team cuts this player after the first year , the final three years do not count against the cap . Any signing bonus , however , ceases to be pro - rated , and the entire balance of the bonus counts against the cap in the upcoming season . NFL Draft . Each April , each NFL franchise seeks to add new players to its roster through a collegiate draft known as " the NFL Annual Player Selection Meeting " , which is more commonly known as the NFL Draft . Teams are ranked in inverse order based on the previous season ' s record , with the team having the worst record picking first , and the second - worst picking second , and so on . Regardless of regular season records , the last two picks of each round go to the two teams in the Super Bowl immediately preceding the draft , with the Super Bowl champion picking last . The draft proceeds for seven rounds . In the past , Rounds 1 – 2 were run on Saturday of draft weekend , rounds 3 – 7 were run on Sunday . During 2010 the league experimented with a new system . Round 1 was run on Thursday night of the draft weekend . Rounds 2 and 3 were run on the Friday night of the draft weekend . Rounds 4 through 7 were run on Saturday . The impact of this change - - according to commentators at ESPN and Sports Illustrated - - was that teams gained more time to make trades for draft picks in the early rounds and that process enhanced the value of the first picks in Rounds 2 and 4 . http : / / www . nfl . com / draft / 2010 and www . si . com Teams are given 10 minutes in the first round of the draft , 7 in the second round and 5 in all other rounds . If the pick is not made in the allotted time , subsequent teams in the draft may draft before them . This happened in 2003 to the Minnesota Vikings . Teams have the option of trading away their picks to other teams for different picks , players , cash , or a combination thereof . While player - for - player trades are rare during the rest of the year ( especially in comparison to the other major league sports ) , trades are far more common on draft day . In 1989 , the Dallas Cowboys traded running back Herschel Walker to the Minnesota Vikings for five veteran players and six draft picks over 3 years . The Cowboys would use these picks to leverage trades for additional draft picks and veteran players . As a direct result of this trade , they would draft many of the stars who would help them win three Super Bowls in the 1990s , including Emmitt Smith , Russell Maryland , and Darren Woodson . The first pick in the draft is often taken to be the best overall player in the rookie class . This may or may not be true , since teams often select players based more on the teams ' needs than on the players ' overall skills . Plus , comparing players at different positions is difficult to do . Still , it is considered a great honor to be a first - round pick , and a greater honor to be the first overall pick . The last pick in the draft is known as Mr . Irrelevant , and is the subject of a dinner in his ( dubious ) honor in Newport Beach , California . Drafted players may only negotiate with the team that drafted them ( or to another team if their rights were traded away ) . The drafting team has one year to sign the player . If they do not do so , the player may reenter the draft and can be drafted by another team . Bo Jackson famously sat out a season in this way . Free agency . General . As defined by the Collective Barganing Agreement ( CBA ) , a free agent is any player who is not under contract to any team and thus has fully free rights to negotiate with any other team for new contract terms . Free agents are classified into two categories : " restricted " and " unrestricted " . Furthermore , a team may " tag " a player as a " franchise " or " transition " , which places additional restrictions on that player ' s ability to negotiate . However , the ability to " tag " is quite limited , and only affects a handful of players each year . Free agency in the NFL began with a limited free agency system known as " Plan B Free Agency " , which was in effect between the 1989 and 1992 seasons . Beginning with the 1993 season , " Plan A Free Agency " went into effect . Restricted free agent . A player who has 3 years of experience is eligible for restricted free agency , whereby his current team has the chance to retain rights to this player by matching the highest offer any other NFL franchise might make to that player . The club can either block a signing or , in essence , force a trade by offering a salary over a certain threshold . In 2006 , these thresholds were as follows : Unrestricted free agent . A player who has four or more years of experience is eligible for unrestricted free agency , whereby his current team has no guaranteed right to match outside offers to that player . This means that players in this category have unlimited rights to negotiate any terms with any team . Free agency changes in 2010 . In 2010 , the CBA was not extended , thus the rules changed so that players don ' t become " Unrestricted Free Agents " until they have at least six years of experience . They will be " Restricted Free Agents " if they have three – five years of experience . There will also be limitations imposed on which clubs are allowed to sign free agents . This is part of a set of rule changes written into the CBA designed to encourage the owners and the NFLPA to negotiate a new CBA : the players lose some free agency rights , and the owners lose the salary cap . Franchise tag . The franchise tag is a designation given to a player by a franchise that guarantees that player a contract the average of the five highest - paid players of that same position in the entire league , or 120 % of the player ' s previous year ' s salary ( whichever is greater ) in return for retaining rights to that player for one year . An NFL franchise may only designate one player a year as having the franchise tag , and may designate the same player for consecutive years . This has caused some tension between some NFL franchise designees and their respective teams due to the fact that a player designated as a franchise player precludes that player from pursuing large signing bonuses that are common in unrestricted free agency , and also prevents a player from leaving the team , especially when the reasons for leaving are not necessarily financial . A team may , at their discretion , allow the franchise player to negotiate with other clubs , but if he signs with another club , the first club is entitled to two first round draft picks in compensation . Banned substances policy . The NFL banned substances policy has been acclaimed by some and criticized by others , but the policy is the longest running in American professional sports , beginning in 1987 . The current policy of the NFL suspends players without pay who test positive for banned substances as it has since 1989 : four games for the first offense ( a quarter of the regular season ) , eight games for a second offense ( half of the regular season ) , and 12 months for a third offense . The suspended games may be either regular season games or playoff games . In comparison to the policies of Major League Baseball and the National Hockey League , the NFL has long been the most strict . While recently MLB and the NHL decided to permanently ban athletes for a third offense , they have long been resistant to such measures , and random testing is in its infancy . Since the NFL started random , year - round tests and suspending players for banned substances , many more players have been found to be in violation of the policy . By April 2005 , 111 NFL players had tested positive for banned substances , and of those 111 , the NFL suspended 54 . A new rule is in the works due to Shawne Merriman . Starting the 2007 season , the new rule would prohibit any player testing positive for banned substances from being able to play in the Pro Bowl that year . Management . Commissioners and presidents Main league offices Franchise owners . Unlike many professional leagues , the NFL forbids corporate owners . Ownership groups must contain twenty - four or fewer individuals , and at least one partner must hold a thirty percent or greater share of the team . The Green Bay Packers are an exemption to the current policy , since they have been a publicly owned stock corporation since before the rule was in place . In recent years , NFL owners and the NFL itself have become politically active , donating millions of dollars to political candidates . Uniform numbers . In the NFL , players wear uniform numbers based on the position they play . The current system was instituted into the league on April 5 , 1973 , as a means for fans and officials ( referees , linesmen ) to more easily identify players on the field by their position . Players who were already in the league at that date were grandfathered and did not have to change their uniform numbers if they did not conform . Since that date , players are invariably assigned numbers within the following ranges , based on their primary position : Prior to 2004 , wide receivers were allowed to wear only numbers 80 – 89 . The NFL changed the rule that year to allow wide receivers to wear numbers 10 – 19 to allow for the increased number of players at wide receiver and tight end coming into the league . Linebackers are allowed to wear numbers between 40 – 49 when all of the numbers 50 – 59 and 90 – 99 are taken . Prior to that , players were allowed to wear non - standard numbers only if their team had run out of numbers within the prescribed number range . Keyshawn Johnson began wearing number 19 in 1996 because the New York Jets had run out of numbers in the 80s . Oakland Raider offensive center Jim Otto wore a 00 jersey during most of his career with the AFL team and kept the number after the leagues merged . Devin Hester is a wide receiver / return specialist for the Chicago Bears but wears number 23 because he was drafted as a cornerback but transferred to wide receiver after his rookie year . Occasionally , players will petition the NFL to allow them to wear a number that is not in line with the numbering system . Brad Van Pelt , a linebacker who entered the NFL in 1973 with the New York Giants , wore number 10 during his eleven seasons with the club , despite not being covered by the grandfather clause . In 2006 , New Orleans Saints running back Reggie Bush petitioned the NFL to let him keep the number 5 which he used at USC . His request was later denied . Former Seattle Seahawks standout Brian Bosworth attempted such a petition in 1987 ( to wear his collegiate number of 44 at the linebacker position which he used at the University of Oklahoma ) , also without success . The Seahawks attempted to get around the rule by listing Bosworth as a safety , but after he wore number 44 for a game against the Kansas City Chiefs , the NFL ruled Bosworth would have to switch back to his original number , 55 . To aid the officials in spotting certain penalties , such as " illegal formation " or " ineligible receiver " , usually only offensive players with numbers 1 – 49 and 80 – 89 are allowed to play at the end or back positions or handle the ball in normal game situations . However , a player wearing 50 – 79 or 90 – 99 may play in an " eligible " position simply by reporting to the referee that he will be doing so . The NFL numbering system is based on a player ' s " primary " position . Any player wearing any number may play at any position on the field at any time , subject to the reporting rules described above . It is not uncommon for running backs to line up at wide receiver on certain plays , or even to have a large offensive or defensive lineman play at fullback or tight end in short yardage situations . Also , in preseason games , when teams have expanded rosters , players may wear numbers that are outside of the above rules . When the final 53 - player roster is established , they are reissued numbers within the above guidelines . Cheerleading . 27 of the 32 NFL teams are supported by their own professional cheerleading squads . These squads attend games and promote the team . The teams without cheerleading squads are the Pittsburgh Steelers , Cleveland Browns , Chicago Bears , New York Giants , and Detroit Lions .