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The 4-3 Defense: The Complete Guide

Posted by John Grayson on

The 4-3 defense is one of the most popular defenses in the NFL and across football at all levels.

Brought to the NFL by Cowboys great Tom Landry originally with the New York Giants as their defensive coordinator, the defense was modernized by Jimmy Johnson at the University of Miami and his modernized version was brought to the NFL, ironically when he replaced Landry with the Dallas Cowboys.

The defense again went through a renaissance in the early 2000’s when the Tampa Bay Buccaneers began running the “Tampa 2” coverage winning a Super Bowl in 2003. 

So in this article we're going to learn more about the 4-3 defense, what it is, and what it can do.

What is the 4-3 Defense?

The 4-3 defense is made up of four defensive linemen, 3 linebackers, and 4 defensive backs.

4-3 Defense Diagram

The defense uses smaller, more athletic players at each position in the “front 7”. The 4-3 defense in a traditional “Under front” uses two 5 technique defensive ends, a 1 technique nose guard and a 3 technique defensive tackle. The 3 technique defensive tackle, is arguably the most important position in the defense. 

Personnel Needed to Run the 4-3 Defense

The two defensive ends are traditional by nature. Playing in a 5 technique the defensive ends can be smaller than defensive tackles in a 3-4. 5 technique defensive ends are only responsible for 1 gap, and contain the quarterback so they are more athletic.

The 1 technique is the biggest lineman of the 4. He is responsible for the strong A gap, usually taking on a double team. The 3 technique is bigger than the 5 techniques, but more athletic and usually a little smaller than the 1 technique. That player is widely regarded as the most important player in the 4-3. The three linebackers go from big to small from strong to weak. The “Sam” aligns to the strength and is usually the biggest of the three linebackers. If the 3 technique is not the most important player, then the Mike linebacker is. A sideline to sideline defender, the Mike linebacker has to have the ability to stop the run and cover the pass. The Will linebacker which lines up away from the defensive strength is the smallest and the most athletic. The defensive backs are traditional. Two safeties a strong safety and a free safety. The strong safety is usually bigger than the free safety. 

Strengths of the 4-3 Defense

The strength of the 4-3 defense is that it is usually very good against the run. There are 7 defenders in the box in the base alignment. With the 5 offensive linemen, the offense needs to add an additional blocker to account for the defenders in the box.

4-3 Defense 1 Gap Run Defense

The defense is also gap sound. Every defender has a gap, as opposed to the 3-4, the defensive linemen have to 2 gap, and the linemen read off of their play. The 4-3 takes some of the reading out of it as each player takes a gap. The four defensive backs allow the defense to play multiple coverages. The 1 technique, is tasked with taking on a double team, so that the 3 technique defensive tackle can play a 1 on 1 block with the offensive guard.

In passing situations, this allows the 3 technique (think Aaron Donald or Warren Sapp) to rush the passer and create pressure up the middle. 

Weaknesses of 4-3 Defense

The defense struggles with today’s modern spread offenses.

The 2x2 formation in today’s modern spread pull the linebackers out of the box, where they are not used to playing. This only leaves 5 defenders in the box and allows the offense to run the football with the 5 offensive linemen blocking. The defense is also very personnel specific. Bigger bodies linebackers struggle to play in a 4-3 defense due to coverage responsibilities. Many defenses remove the Sam linebacker, and go with Nickel personnel to combat modern offensive schemes. 

How Do Offenses Like to Attack the 4-3 Defense?

Modern offenses like to attack the 4-3 defense by spreading it out. 

Displacing the “Sam” linebacker out of the “box” and matching him up with a more speedy wide receiver puts him in conflict with the Sam, who is a more downhill, in the box type of linebacker traditionally struggles in coverage.

4-3 Defense vs Spread Formation

Most offenses spread the field, causing a 4-3 defense to change out of their base personnel and into a “nickel” personnel. The defense is forced to add another defensive back to defend against the modern spread offenses. An offense will also try and run it to the edge to attack a 4-3 defense.

Against an offense that has extra eligible blockers in addition to the offensive line, like a fullback or an H back, the 4-3 will naturally add more players to the box. This is slight of hand from the offense. Having in line blockers gives the appearance of an inside run, but with modern outside zone schemes, your edge will be outflanked.

Adding more players to the box leaves you vulnerable on the edge. If your 5 technique defensive end gets hook blocked by an offensive tackle, the inline H or fullback will lead up to your Sam, or in some cases the safety and the offense will have numbers on the edge of your defense. 

Common Blitzes from the 4-3 Defense

Now let's look at a couple of common ways that the 4-3 defense can create pressure with blitzes.

Will Edge Blitz

4-3 Defense Will Edge Blitz

A simple blitz out of the 4-3 sends the Will linebacker off the weak edge as a fifth rusher. When the weak side end slants to the B gap, and the Will rushes off the weak edge, combined with a nose playing his regular A gap, the weak side of the defense now has a hat in every gap. To the strength the 3 tech slants into the A gap (you don’t have to slant the 3 tech). The mike will be a B gap player, and the strong end will take the normal C gap. 

4-3 Defense Zone Blitz DE Drop

4-3 Defense Blitz

Blitz 2 has a defensive end dropping into coverage. The line, from strong to weak, the strong defensive end long sticks to the strong A gap. The Nose slants across the center. The 3 technique slants to the C gap while the weak defensive end drops into coverage. This is a less traditional blitz from the 4-3. The Sam comes off the strong edge, and will be a contain player, the mike linebacker blitzes the B gap, creating a 5 man rush. The coverage behind is a 3 under, 3 deep coverage. 

Common Coverages from the 4-3 Defense

Now let's look at some examples of pass coverages from the 4-3 defense.

4-3 Defense Tampa 2

4-3 Defense Tampa 2 Coverage

Cover 1 is the “Tampa 2” coverage made famous by the early 2000’s Tampa Bay Buccaneers teams. In Tampa 2, each safety has a deep half coverage. Both corners play the flat. The Sam and the Will are hook to curl players. Where the Tampa 2 differs is, the Mike linebacker drops to the “deep hole” of the defense providing support to the middle of the field, where the two safeties divide. The mike linebacker provides help on posts commonly run as “cover 2 beaters.” 

4-3 Defense Cover 3

4-3 Defense Cover 3

Next is cover 3. The Strong safety starts as a 2 high player giving the appearance of cover 2, 4, or cover 2 man but falls to linebacker depth for coverage. The two corners and free safety create a 3 deep coverage. Linebackers play hook to curl. This coverage is a great change up to normal 2 high coverages in the 4-3. 

What Coaches/Teams Use the 4-3 Defense?

2000's Tampa Bay Buccaneers

The great Tampa Bay Buccaneers teams of the early 2000’s famously ran the “Tampa 2” and used that coverage and the 4-3 defense to be one of the more dominant defenses of the 21st century. Many of the players that played in this defense, became the prototype players when discussing personnel in the 4-3. Warren Sapp was a dominant 3 technique, Derrick Brooks was the Will linebacker, John Lynch a hard hitting strong safety, Simeon Rice the dominating 5 technique.

Derrick Brooks 4-3 Defense

From the Tampa Bay Buccaneers, came the  2006 NFC Champion Chicago Bears. The Bears hired Lovie Smith as their head coach who was an assistant on the great Tampa Bay teams. The Bears inside linebacker, Bryan Urlacher is looked at as the prototype linebacker in the 4-3, Tampa 2 system for his ability to drop deep between the two safeties and cover the middle of the field. Urlacher though, was big enough to be an in the box run stuffer as well.  

Montini Catholic HS (IL)

Mike Bukovsky of Montini Catholic High School, in Lombard, Illinois used the 4-3 defense to win 6 state championships as the defensive coordinator. The Broncos won their first state title in 2005, followed by 4 straight in 2009, 2010, 2011, & 2012. In 2013 & 2014 the Broncos finished 2nd in the state. The Broncos won another state title with Bukovsky as the defensive coordinator in 2015 going undefeated, capping off a run of 7 straight state title games. In 2018, with Bukovsky now as the head coach and the defensive coordinator, the Broncos used the 4-3 defense to secure another runner up finish leaving the Broncos with 7 trophies in the decade under Bukovsky’s tutelage.

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