<P> The 4--3 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 . </P> <P> 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 he 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 . </P> <P> 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 . </P> <P> NFL teams that use the 4--3 defense as of 2017 include the Dallas Cowboys, Atlanta Falcons, Minnesota Vikings, Carolina Panthers, Cincinnati Bengals, Jacksonville Jaguars, Oakland Raiders, Detroit Lions, Cleveland Browns, New England Patriots, Tampa Bay Buccaneers, Seattle Seahawks, Buffalo Bills, Philadelphia Eagles, Los Angeles Chargers, Miami Dolphins, New Orleans Saints, San Francisco 49ers, and the New York Giants . The Philadelphia Eagles returned to running a 4--3 defense for the 2016 season, after switching to the 3 - 4 at the start of 2013 . The New York Jets used variations of the 4--3 for the 2012 NFL season against spread offenses, but will stick with the 3 - 4 defense as its base . The Patriots run a hybrid defense including elements from both the 4 - 3, and 3 - 4 defense . </P>

What type of defense do the seahawks run