In American football, the 3–4 defense is a common defensive alignment consisting of three down linemen and four linebackers. It is called a "base defense" because it will readily switch to other defensive alignments (such as a nickel defense or a dime defense) as circumstances change. Alternatively, some defenses use a 4–3 defense: four down linemen and three linebackers.
Overview
The 3–4 defense incorporates three defensive linemen – two defensive ends and one nose tackle, who line up opposite the other team's offensive line. Those three players are responsible for engaging the other team's offensive line, allowing the four linebackers to either rush the quarterback or drop back into coverage, depending on the situation. While the role of the defensive linemen is fairly consistent, the linebackers allow for the flexibility and versatility of the 3–4 scheme, and give defensive coaches nearly limitless options to confuse the other team's players and coaches. Depending on the situation, any number of linebackers can blitz, fake a blitz, "spy" the quarterback or running back, or cover receivers. In key situations, a rush linebacker may be sent to cover the flat on the opposite side of the blitzing defensive back; this is called a "zone blitz".
After becoming the predominant defensive alignment in the late 1970s and early 1980s, the 3–4 defense declined in popularity over the next two decades, but experienced a resurgence in the 2000s among both professional and college football teams. As of 2022, NFL teams that regularly incorporate the 3–4 defensive alignment scheme as a base include the Green Bay Packers, Los Angeles Rams, Los Angeles Chargers, Seattle Seahawks, Pittsburgh Steelers, Baltimore Ravens, Atlanta Falcons, New York Giants, Minnesota Vikings, Miami Dolphins, Tampa Bay Buccaneers, Denver Broncos, New England Patriots, Tennessee Titans, Jacksonville Jaguars and Arizona Cardinals.
The Philadelphia Eagles ran the 3–4 from 2013 to 2015 but switched back to the 4–3 for the 2016 season. The New England Patriots returned to a 4–3 defensive front at the end of the 2011 season but use more of a hybrid employing some 3–4 looks. The Cleveland Browns used the 3–4 in 2016, but returned to the 4–3 in 2017 under new defensive coordinator Gregg Williams, and kept the formation under new defensive coordinator Steve Wilks.
The New York Jets announced that despite hiring Gregg Williams as their new defensive coordinator they would continue to employ the 3–4 defense in 2019, opting to stay with the scheme that better suits their current roster instead of switching to the defense Williams usually used.
In 2019, the Tampa Bay Buccaneers switched to a 3–4 defense under new defensive coordinator Todd Bowles, who previously ran the 3–4 defense with the New York Jets. Bowles became the Buccaneers' head coach in 2022 following Bruce Arians's retirement.
The Carolina Panthers ran a 3–4 base defense in the 2019 season for the first time since the late 1990s under their first head coach, Dom Capers.
The Arizona Cardinals ran the 3–4 under coordinators Todd Bowles and James Bettcher from 2013 to 2017, but switched to the 4–3 in 2018 under head coach Steve Wilks, who ran the 4–3 as defensive coordinator for Ron Rivera with the Carolina Panthers. In 2019, the Cardinals returned to the 3–4 under new defensive coordinator Vance Joseph, the former Broncos head coach hired by new Arizona coach Kliff Kingsbury.
Soon after being hired as Rams head coach in 2017, Sean McVay named Wade Phillips as the team's defensive coordinator. Phillips switched the Rams to the 3–4, the first time the team had used it since the early 1990s, prior to the franchise's move to St. Louis. Phillips was fired at the conclusion of the 2019 season.
The Kansas City Chiefs switched to a hybrid 4–3 defense in the 2019 season with the hiring of defensive coordinator Steve Spagnuolo.
The Pittsburgh Steelers have used the 3–4 as their base defense since 1982, the season after 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 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.