3 – 4 defense In American football , the 3 – 4 defense is a defensive alignment consisting of three down linemen and four linebackers . The 3 – 4 defense declined in popularity over the years , but has found renewed use by modern professional and college football teams . The 3 – 4 defense is so named because it involves 3 down linemen and 4 linebackers . There are usually 4 defensive backs . Teams that regularly incorporate the 3 - 4 defensive alignment scheme include the Cleveland Browns , San Diego Chargers , Green Bay Packers , Baltimore Ravens , Arizona Cardinals , Indianapolis Colts , Kansas City Chiefs , New York Jets , San Francisco 49ers , Pittsburgh Steelers , Washington Redskins , New Orleans Saints , Philadelphia Eagles and Houston Texans . The Cardinals already incorporate the 5 – 2 defense , an older variation of the 3 – 4 , in some of their defensive schemes . The Miami Dolphins have also incorporated elements of the 3 – 4 defense into their scheme , under defensive coordinator Mike Nolan , but with the hiring of Kevin Coyle as their new defensive coordinator , the Dolphins will switch to a 4 - 3 Defense under new coach Joe Philbin . The Ravens run a hybrid defense and occasionally shift to 4 – 3 schemes during games . With the hiring of defensive coordinator Dom Capers , the Green Bay Packers have switched to a 3 – 4 defense ( 2009 ) . With the hiring of Chuck Pagano as their new Head Coach , the Indianapolis Colts have switched to 3 - 4 Defense . The Buffalo Bills installed a 3 – 4 scheme to begin the 2010 season , but made frequent use of 4 – 3 sets as the season progressed , and will stick with the 4 - 3 for 2012 following the signing of free agent defensive end Mario Williams . Under defensive coordinator Wade Phillips , the Houston Texans have adopted the 3 – 4 defensive scheme for the 2011 season . The Dallas Cowboys will switch to the 4 - 3 Defense with the hiring of Monte Kiffin as their Defensive Coordinator . Sean Payton announced that the Saints will switch to the 3 - 4 Defense for the 2013 season , and the Cleveland Browns will switch to a 3 - 4 " stick - em " defense . With the hiring of Chip Kelly as Head Coach and Billy Davis as Defensive Coordinator , the Eagles will shift to a hybrid defense that will incorporate 3 - 4 and 4 - 3 schemes . Typically , there are two major variations of the 3 – 4 defense . Both variations are directly related to coverage schemes on obvious passing downs . For the first type , the outside linebackers will rush the quarterback , the great majority of the time . This defensive scheme is largely attributed to Dick LeBeau , although there is some discussion that Joe Collier of the Denver Broncos " Orange Crush " was the actual originator of the " NFL 3 – 4 " . In the 1970s the Miami Dolphins would bring in Linebacker Bob Matheson ( number 53 ) to be a fourth linebacker in passing situations , a formation known as the " 53 Defense . " On key situations , the rush linebacker will be sent to cover the flat on the opposite side of the blitzing defensive back ; this is the infamous " zone blitz " . The other common 3 – 4 defense is typically associated with the New England Patriots . This scheme requires outside linebackers to have the ability to back pedal and drop into coverage . Of course they do rush the passer at times , it is just that they are much more likely to drop into coverage . | The Chicago Bears are the only NFL team that have never used the 3 – 4 as their base defense . Before the 2010 season , the Washington Redskins had also never run a base 3 – 4 , but under the direction of new defensive coordinator Jim Haslett , the Redskins have adopted the 3 – 4 and its many variants , such as the 2 – 4 – 5 and the 1 – 5 – 5 , based on formations used by the Pittsburgh Steelers . Conversely , the Steelers have used the 3 – 4 as their base since 1982 , the season after Pro Football Hall of Fame defensive tackle Joe Greene and end L . C . Greenwood retired . In fact , the Steelers were the only NFL team to use the 3 – 4 defense during the 2001 NFL season , but finished the season as the number one defense in the NFL . It is believed that the Steelers success with the 3 – 4 defense is the primary reason why many NFL teams have started returning to the formation . The 3 – 4 defense was originally devised by Bud Wilkinson at the University of Oklahoma in the 1940s . Chuck Fairbanks learned the defense from Wilkinson and is credited with importing it to the NFL . The 1972 Miami Dolphins were the first team to win a Super Bowl with the 3 – 4 defense , going undefeated and using number 53 , Bob Mathison as a down lineman or rushing linebacker . When the Oakland Raiders defeated the Philadelphia Eagles in Super Bowl XV , it marked the first Super Bowl in which both teams used the 3 – 4 as their base defense . Also notable , the Big Blue Wrecking Crew , the defensive unit for the 1986 New York Giants who won Super Bowl XXI , was a 3 – 4 defense and featured all - time great Lawrence Taylor as outside linebacker . By the mid - 1990s , only a few teams used a 3 – 4 defense , most notably the Buffalo Bills and Pittsburgh Steelers . Defensive line . The defensive line is made up of a " nose tackle " ( NT ) and two " defensive ends " ( DEs ) . Linemen in 3 – 4 schemes tend to be larger than their 4 – 3 counterparts to take up more space and guard more territory along the defensive front . 3 – 4 defensive ends were usually defensive tackles ( DTs ) when entering at first . They must be strong at the point of attack and are aligned in most cases head - up on an offensive tackle . First and foremost , they must control run gaps . Size and strength become more of a factor for linemen in 3 – 4 defenses than in 4 – 3 defenses because they move primarily within the confines of line play and seldom are in space using athletic ability . Ideally 3 – 4 DEs should weigh and be able to beat double teams by getting a push . The 3 – 4 nose tackle is considered the most physically demanding position in football . His primary responsibility is to control the “ A ” gaps , the two openings between the center and guards , and not get pushed back into his linebackers . If a running play comes through one of those gaps , he must make the tackle or control what is called the “ jump - through ” — the guard or center who is trying to get out to the linebackers . The ideal nose tackle has to be much bigger than 4 – 3 DTs , weighing around 330 pounds or more . Ted Washington is considered the prototypical nose tackle of this era . “ In his prime , Ted Washington was the ideal guy , ” says an AFC pro personnel director . “ He was huge , had long arms , and you couldn ' t budge him . He could hold off a 320 - pound lineman with one hand and make the tackle with the other . ” Since most college teams run a 4 – 3 defense , most college DTs are more of a 4 – 3 tackle than a true nose tackle , which makes good 3 – 4 NTs hard to find . The base position of NT is across from the opposing team ' s center . This location is usually referred to as " zero technique " . The two DEs flank the NT and line up off the offensive guards . The location off the offensive guard is usually referred to as " three technique " . Some 3 – 4 teams ( such as the Pittsburgh Steelers ) use the three down linemen primarily to occupy the offensive linemen . In such systems the defensive linemen are assigned two " gaps " to defend . The NT is responsible for defending plays which occur in the spaces , or gaps , between the center and guards . Each of those spaces is called an " A " gap . Flanking the NT , DEs defend the gaps on either side of the tackle he lines up across from . Each guard - tackle gap is a " B " gap and the space outside each tackle is called a " C " gap . Other 3 – 4 teams ( such as the San Diego Chargers and the Dallas Cowboys ) primarily make each lineman responsible for only one gap . According to former general manager Randy Mueller , “ the 3 – 4 defensive end is easier to identify and find when it comes to scouting and acquiring personnel , ” while 4 – 3 DEs “ are rare and hard to find and therefore very expensive to keep . There is no question that speed pass rushers are very much an impact position on the football field and their cap numbers reflect that . On the other hand , 3 – 4 defensive ends can be found easier and are much less expensive when it comes to ‘ cap dollars ’ . ” Linebackers . In a 3 – 4 defense , four " linebackers " ( LBs ) are positioned behind the defensive line . The linebacker unit is made up of two " inside linebackers " ( ILBs ) flanked by two " outside linebackers " ( OLBs ) . The OLBs often line up closer to the line of scrimmage than the ILBs , but may also be positioned at the same depth or deeper in coverage than the ILBs ( though this is somewhat rare ) . Strengths of the 3 – 4 include speedy ILBs and OLBs in pursuit of backs in run defense and flexibility to use multiple rushers to confuse the quarterback during passing plays without being forced into man - to - man defense on receivers . Most teams try to disrupt the offense ' s passing attack by rushing four defenders . In a standard 4 – 3 alignment , these four rushers are usually the four down linemen . But in a 3 – 4 , the fourth rusher is usually a linebacker , though many teams , such as the Pittsburgh Steelers and Baltimore Ravens , use a talented safety to blitz and confuse the coverage , giving them more defensive options in the same 3 – 4 look . However , since there are four linebackers and four defensive backs , the fourth potential rusher can come from any of eight defensive positions . This is designed to confuse the quarterback ' s pre - snap defensive read . A drawback of the 3 – 4 is that without a fourth lineman to take on the offensive blockers and close the running lanes , both the defensive linemen and the linebackers can be overwhelmed by blocking schemes in the running game . To be effective , 3 – 4 linebackers need their defensive line to routinely tie up a minimum of four ( preferably all five ) offensive linemen , freeing them to make tackles . The 3 – 4 linebackers must be very athletic and strong enough to shed blocks by fullbacks , tight ends , and offensive linemen to get to the running back . In most cases , 3 – 4 OLBs lead their teams in quarterback sack s . Usually , teams that run a 3 – 4 defense look for college “ tweeners ” — defensive ends that are too small to play the position in the pros and not quite fluid enough to play outside linebacker in a 4 – 3 defense — as their 3 – 4 outside linebacker . The wisdom of this strategy is demonstrated in the career of Harry Carson , who played as a defensive lineman in his college career and then went on to become a Hall of Fame ILB for the New York Giants in the 70 ' s and 80 ' s . According to NFL coach Wade Phillips , 3 – 4 linebackers “ are a little bit cheaper , and you can find more of them , ” while “ it ' s harder to find defensive linemen to play a 4 – 3 and pay for all of them . ” Secondary . The 3 – 4 defense generally uses four defensive backs . Two of these are safeties , and two of them are cornerbacks . A cornerback ' s responsibilities vary depending on the type of coverage called . Coverage is simply how the defense will be protecting against the pass . The corners will generally line up 3 to 5 yards off the line of scrimmage , generally trying to " Jam " or interrupt the receivers route within the first 5 yards . A corner will be given one of two ways to defend the pass ( with variations that result in more or less the same responsibilities ) : zone and man - to - man . In zone coverage , the cornerback is responsible for an area on the field . In this case , the corner must always stay downfield of whomever it is covering while still remaining in its zone . Zone is a more relaxed defensive scheme meant to provide more awareness across the defensive secondary while sacrificing tight coverage . As such , the corner in this case would be responsible for making sure nobody gets outside of him , always , or downfield of him , in cases where there is no deep safety help . In man coverage , however , the cornerback is solely responsible for the man across from him , usually the offensive player split farthest out . The free safety is responsible for reading the offensive plays and covering deep passes . Depending on the defensive call , he may also provide run support . He is positioned 10 to 15 yards behind the line of scrimmage , toward the center of the field . He provides the last line of defense against running backs and receivers who get past the linebackers and cornerbacks . He must be a quick and smart player , capable of making tackles efficiently as well as reading the play and alerting his team of game situations . The strong safety is usually larger than the free safety and is positioned relatively close to the line of scrimmage . He is often an integral part of the run defense , but is also responsible for defending against a pass ; especially against passes to the tight - ends . NFL teams using a 3 – 4 base defense as of 2013 . While Patriots coach Bill Belichick hasn ' t formally announced a shift to the 4 – 3 , media speculation has been rampant after the team acquired 4 – 3 specialists like Albert Haynesworth , Mark Anderson , Shaun Ellis , and Andre Carter . The Patriots debuted their 4 – 3 defense in week one of the 2011 season . Five of New England ' s six sacks in its week one victory over the Miami Dolphins came from defensive linemen . However , during Super Bowl XLVI , the Patriots began the game using a 3 - 4 Defense . As of 2012 , the team has returned to a 4 - 3 base . While many still consider the Baltimore Ravens ' defense a 3 – 4 , it has shifted towards a 4 – 3 scheme since 2006 when half their games were in a 4 - 3 base defense . The Ravens ' primary pass - rusher , Terrell Suggs , played the majority of his snaps in 2010 as a true defensive end . The 49ers run a hybrid 3 – 4 defense that attack offenses using both 3 - 4 and 4 - 3 principles . The 49ers ' hybrid rush linebacker , Aldon Smith , occasionally lines up at defensive end . With the hiring of Kevin Coyle as their Defensive Coordinator , the Miami Dolphins will make a switch to a 4 - 3 Defense . Coyle was a defensive assistant under Head Coach Marvin Lewis in Cincinnati , which ran a 4 - 3 Defense , but new Head Coach Joe Philbin ' s Packers ran a 3 - 4 Defense with Dom Capers as Defensive Coordinator and Philbin was the Offensive Coordinator . On January 31 , Bills coach Chan Gailey announced to Sports Illustrated that the Bills will switch to a base 4 - 3 Defense for the 2012 season , though they will continue to use variances of a 3 - 4 Defense . With the hiring of Chuck Pagano as Head Coach , the Indianapolis Colts will go to a 3 - 4 Defense , which will likely involve moving pass rushers Dwight Freeney and Robert Mathis from Defensive End to Outside Linebacker . It is now rumored that Freeney will probably get traded to a team that runs a 4 - 3 Defense . The New York Jets will use a base 4 - 3 Defense for the 2012 Season with the addition of Quinton Coples as a Pass Rusher , but will switch to a 3 - 4 Defense on occasion . The Jets decided to stick to the 3 - 4 Defense as its base defense for the 2012 Season . The Kansas City Chiefs are expected to return to a 4 - 3 Defense with Andy Reid being named their Head Coach . Reid prefers a 4 - 3 scheme , which he operated in Philadelphia with Jim Johnson and subsequent Defensive Coordinators . However , with the hiring of Bob Sutton from the New York Jets as Defensive Coordinator , the Chiefs have decided to remain a 3 - 4 Defense under Andy Reid . The Dallas Cowboys will switch to a 4 - 3 Defense with the hiring of Tampa 2 specialist Monte Kiffin as their Defensive Coordinator . When the Cleveland Browns hired Rob Chudzinski as a head coach , it was believed he wanted an attacking 3 – 4 defense . The hire of former Arizona Cardinals defensive coordinator for the same position in Cleveland backs up that belief . It is believed that newly hired Philadelphia Eagles coach , Chip Kelly , would change the Eagles defense to 3 - 4 . Defensive coordinator Billy Davis announced that he will implement the " Predator " , a hybrid defense that incorporates both 4 - 3 and 3 - 4 principles . On January 22 , New Orleans Saints Head Coach Sean Payton fired Defensive Coordinator Steve Spagnuolo and announced that team will shift to a 3 - 4 Defense . The hiring of Rob Ryan as defensive coordinator confirms the switch .