4 – 4 defense In American football , the 4 – 4 defense is a defensive alignment consisting of four down linemen and four linebacker s . The 4 – 4 defense is based on speed , athleticism and intelligence rather than on size and strength . Versatility is key because every player may have to change roles from one play to the next . It is an attacking defense stocked with multiple blitz packages that can easily be concealed and altered . The top priority of the 4 – 4 defense is stopping the run by keeping eight men close to the line of scrimmage . This also makes it difficult for the offense to identify where the pressure comes from when the defense blitzes . One other significant advantage of the 4 – 4 defense is its flexibility and adaptability . The 4 – 4 can shift into nickel or dime coverage quickly and easily . On the other hand , the 4 – 4 defense is vulnerable to the big play , both through the air and on the ground . Running backs with breakaway speed can be very successful against the 4 – 4 . Once the running back clears the front eight , they may only have one or two men to beat in the secondary . Another way this defense can be exposed is with the deep pass . The cornerbacks are often left exposed without safety help , either in man coverage or a 3 deep zone . If a Wide receiver manages to clear his defender , there may be nothing between him and the End zone . However , even if a Wide receiver does open up deep , the 4 - 4 defense can bring considerable pressure on the opposing Quarterback to stop him delivering the ball . Defensive tackles . While size is definitely a plus for defensive tackles in the 4 – 4 , its not as important as quickness and the ability to use leverage to manipulate the offensive linemen . It ' s imperative for the defensive tackles to hold their ground . They cannot allow themselves to get turned around and under no circumstances can they allow themselves to be base blocked , one on one . Again , size is great and certainly helps , but a smaller tackle can be just as effective if he is a good technician . In the base 4 – 4 , the defensive tackles will generally line up in the B gap in a 3 technique ( outside eye of the guard ) . Depending on the read , the defensive tackle will either be asked to penetrate the line of scrimmage , or hold his ground and attempt to take on both the guard and offensive tackle . Defensive ends . The defensive end ' s primary role in the 4 – 4 defense is to get to the quarterback as fast as possible . They need to be strong enough to fight their way past offensive tackles ; but they also need to be athletic enough to act as linebackers because there are plenty of scenarios in the 4 – 4 defense that require the defensive ends to drop into coverage , just as an outside linebacker would do . The ends should do whatever they can to get to the quarterback and on running plays they should pursue down the line of scrimmage , but be careful not to over - commit as they need to be ready for a potential cutback . Inside linebackers . There are two inside linebackers in the 4 – 4 scheme sometimes known as the Mike and Buck linebackers . While they both play inside , Buck will shade to the strong side of the offense , Mike shades to the weak side . It is important for these inside backers to be aggressive and have a nose for the ball . As in most defenses , the Mike backer acts as the quarterback of the defense and is often the defensive leader . The primary responsibility of both Mike and Buck is to stop the run . The Buck backer will generally be more active in pass coverage than the Mike . Because of this , the Buck backer needs to be athletic enough to drop and almost play like a strong safety . Outside linebackers . As there are two inside linebackers , there are also two outside linebackers . These outside backers are known as Sam and Rover . The Sam linebacker typically sticks to the strong side . Sam does his fair share of blitzing , however he also needs to play the run and will usually be relied upon to cover the tight end or potentially a back out of the backfield . Rover will generally play on the weak side , however he can be moved to just about anywhere to better suit the defensive call or adjustment . The rover is probably the single most versatile position in the 4 – 4 defense . Depending on the call and the personnel in place , the Rover ’ s job could be purely to get after the quarterback or to drop into coverage . In a blitzing situation , the Rover is the most likely player to get to the quarterback . The Rover position can be played by a variety of athletic types ranging from an outside linebacker , to a strong safety . The " Rover " linebacker is sometimes also known as the " Will " position ( Sam comes from strong side linebacker , and thus Will signifies the weak side backer ) . Secondary . The cornerbacks are often on islands in man coverage or in a deep zone , and they need to possess exceptional speed and change of direction skills . They also need to be intelligent when diagnosing the play and when in zone coverage , must be able to play the ball . The corners will generally line up 3 to 5 yards off the ball , but will rarely jam because of the risk of a big play . If the corner jams and the receiver is able to get past him , it has a high probability of ending up a big play for the offense . Of course it helps to have corners that can assist in run support , however , their primary responsibility is to shut down any receiving threat they are assigned to . The safety in the 4 – 4 defense should be one of the team ’ s better athletes . He needs to be fast enough to play in coverage and strong enough to help against the run . He needs to have a nose for the ball and be able to diagnose the play to put himself in a position to make a play . The safety will almost always be assigned to the deep middle of the field , however he can also be blitzed in various packages .