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Chalk Talk: The History and Application of the 4-3 Defense

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In the first of a three-part series, we take a look at the second most common defensive scheme in the NFL today.

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Two constants in professional football are change and adaptation. Exotic blitz packages and base defenses run out of the nickel now serve as the norm while, decades ago, were never even a glimmer in the eyes of defensive coordinators across the league.

Back in the 1930’s, it was common practice to stack the defensive line with as many as seven linemen. At that time, professional football was still in it’s infancy, and most teams simply ran the ball down their opponent's throat. With little down-field passing, it wasn’t yet necessary to assign more than two lone defensive backs with downfield responsibilities.

In 1933, the passing rules changed and became more friendly to offenses that could throw the ball downfield. By the 1940’s, vertical timing offenses were beginning to permeate the league. As the Browns dominated the All-American Football Conference from 1946 through 1949 with this new strategy, other teams rushed to design the antidote. After joining the NFL in 1950, the Browns beat every team on their schedule that season except the New York Giants; losing to them twice.

The Giants, then coached by Steve Owen, had begun to employ a new defensive scheme called a 6-1-4 alignment which allowed the two defensive ends to drop back into pass coverage. One of the Giants’ defensive backs, a player named Tom Landry, would actually teach and install the defense for the rest of the team. In 1956, Landry hung up his cleats and served as defensive coordinator. Opposite Vince Lombardi as the offensive coordinator, Landry installed a new scheme that helped the Giants win a Super Bowl, therefore causing an avalanche of copy cat teams hungry to match their success. Later, as a coach of the Dallas Cowboys, Landry would refine this defensive system into what is now known as the 4-3 defense.

The numbers 4-3 refer to the number of defensive linemen and linebackers respectively. The defensive line consists of two defensive tackles on the inside and two defensive ends on the outside. In an "over" or "under" 4-3 system, one of the defensive tackles is a nose tackle; while in an even 4-3 system, there is no nose tackle, just a left and right defensive tackle. The nose tackle must be large and strong, and his two most important jobs are stuffing the run and taking on double teams to free up the linebackers to make a play. The three-tech defensive tackle must be faster than the nose tackle, prevent the run, keep the guard off the linebackers, and also be able to rush the passer.

To employ a strong 4-3 system, a team needs two effective pass rushers at defensive end. But as Mike Tanier noted, "Teams that want to use a standard 4–3 scheme often face a dilemma: there aren't enough great defensive ends to go around. Players like Julius Peppers or Dwight Freeney come along about once per year in the draft." These players are incredibly athletic and agile while also possessing an ability to get up the field quickly.

4-3 defensive ends set the edge and keep the quarterback from rolling out of the pocket and gaining extra yards. They must be strong enough to take on a tackle, tight end, and sometimes even a double team. Along with strength, they must possess the intelligence and ability to instantly discern a run from a pass. Ends must also be explosive pass rushers complete with a plethora of techniques (swim-move, dip, spin-move, club move, etc.) to help them disengage from blocks and pursue the quarterback.

Behind the four defensive linemen are three linebackers; one inside linebacker and two outside linebackers. The inside linebacker, also referred to as the middle linebacker, or "Mike", serves as the quarterback of the defense. Often the largest and strongest of the linebackers, the "Mike" must be as smart as he is athletic to stop the run and fall back into pass coverage. Above average speed is needed to cover receivers 10-20 yards downfield. The Carolina PanthersLuke Kuechly epitomizes this role.

The two outside linebackers are referred to as the strong-side, or "Sam", and the weak-side, or "Will". The "Sam" is usually the larger and stronger of the two as he must line up against the strongest blockers on the offensive line like left tackle and tight end. His job is to attack the run, take on blockers, and blitz occasionally. As the "Sam" takes on the dirty work, the "Will" can roam more freely while concentrating on pass coverage, protecting against the screen pass, and blitzing the quarterback.

Strengths of the 4-3 Defense

1) Generates pass rush from front four with minimal blitzing.

2) Allows defense to drop seven players into coverage and still get pressure on the quarterback.

3) Above average against the run as four linemen clog the lanes.

4) Allows linebackers freedom to go sideline to sideline in pursuit of ball carriers.

5) Roles are clearly defined, therefore shortening the learning curve for younger players.

Weaknesses of the 4-3 Defense

1) With only three linebackers, there is a liability against the passing game, especially against athletic receiving tight ends and scat backs.

2) Fails without effective pass rushing defensive ends and a sure tackling, excellent in coverage middle linebacker.

3) Easier for opposing quarterbacks to spot deficiencies and exploit mismatches.

Next week, Chalk Talk will dive into the other predominant defensive scheme in the NFL, the 3-4. After learning more about the systems themselves, I will then take a look at the Saints' projected roster and attempt to make a prescription for the best scheme fit for our personnel.