4-3, 3-4 or both?

A few years ago, Bill Belichick stood in front of a room full of coaches and said, “regardless of your personnel, the 3-4 is more flexible.” The longtime Patriots head coach has been widely viewed as a defensive genius since his days as the defensive coordinator of the New York Giants. He’s always believed in the 3-4 defense because of the aforementioned flexibility, but now it appears that he is going away from the popular front, reverting back to the 4-3. Why would a coach who has long been associated with the 3-4 abandon it after running it the majority of his coaching career?

The truth is, Bill Belichick has always been a 4-3 guy, but like his friend Nick Saban, he’s played it out of a 3-4 shell, and he’s not abandoning the 3-4. Belichick has often rushed four defenders out of the 3-4 shell while dropping three into coverage, thus making it a 4-3 rush concept. However, it has always been tough to nail down Belichick’s true scheme because of the various concepts he throws at NFL offenses. We’ve seen Belichick use various fronts based off of the personnel that he has to work with. The personnel is used to the strengths of the players, which Belichick has a keen eye for identifying in his guys, which also is why the players are often in a rotation. When labeling the various fronts that NFL defenses throw at their opposition, it is important to note the covered and uncovered offensive lineman as well as the techniques used by the defenders. All fronts in football can be narrowed down to five identifications, and they are as follows:

  1. Even – Center is uncovered.
  2. Under – 3 technique is to the strong side of the formation presented by the offense.
  3. Over – 3 technique is to the weak side of the formation presented by the offense.
  4. Okie – Center is covered, Guards are uncovered.
  5. Jam/Bear – Center and Guards are covered.

The five fronts listed above are important to keep in mind when identifying fronts because they are used in both the 3-4 and 4-3 fronts, which consequently minimizes the differences between the two fronts. The former, the 3-4, is more versatile and flexible, but the latter, the 4-3, can also be flexible depending on how the players are used and what kind of talent level they possess.

Moreover, the most important thing to note of football defensive fronts is that they are made up of techniques. These techniques are along the defensive line as well as the linebackers. The techniques that are used by the fronts are helpful in determining the assignments given to the defenders. For example, if a team runs two 3 techniques along the defensive line, it means the MLB (middle linebacker) is head up on the center and is responsible for two gaps. Below is a diagram showing techniques and gaps that are used by NFL defenses.



The gaps above are assigned as responsibilities for players. A player may be assigned to control a single gap, meaning he is 1 gapping. However, a player could be assigned two gaps, such as both A gaps, which means he is 2 gapping. Both defensive linemen and linebackers can be assigned one or two gaps, depending on the techniques used in the front. A successful defense must be able to control the gaps of the trenches. Each of the techniques and assigned gaps above apply to the New England Patriots’ defensive front seven.

As stated, the Patriots defense is notorious for giving different looks to offenses each week. The Patriots defense can be defined as multiple because of the endless concepts and fronts they pair and a lot of the stuff they do is recycled from past years. Belichick has often stated that football is a cycle, often old becoming new and new becoming old as the years pass by. This most certainly applies to the Patriots defense, as will be seen later.

This preseason, the Patriots have mainly been using the Over and Under fronts against offenses. The Over front is one that can be considered an Odd front because it covers the Center. It puts a defensive tackle at the 3 technique at the strong side of the formation while the 1 technique is on the weak side. When they have gone to the Under front, it has put the 3 technique tackle on the weak side of the formation, or in the direction of the tight end, while the 1 technique on the strong side. The nose tackle is at the 1 technique (strong side in Under front, weak side in Over front).

They have also often rolled up their strong side linebacker on the tight end or the strong side of the formation in a 9 technique. The alignment of the strong side linebacker on the strong side of the formation in a 9 technique is called an Under shift. Another alignment they have done with the strong side linebacker is across the tight end, which puts the linebacker at an 80 technique (LBs have an added 0 on their techniques if not on the line) and in an Over shift.

The image above is shown out of a 3-4 front but is ran by the Patriots out of a 4-3 front. This front, the Under (Odd because of center covered), has been one of the most commonly run fronts by the Patriots this preseason and the reason is because of its versatility and flexibility. The WILL (W) can stand up in a two-point or have their hand in the dirt in a three-point stance, as the Patriots have done this preseason while the SAM (S) is head up on the tight end in an Under shift. This front allows the Patriots to slide in and out of the 3-4 defense while keeping their techniques the same.



In the image above, the Patriots have their linebackers over-shifted. The strong side linebacker is across the tight end, which suggests that it is an Over shift.

In this image, the Patriots defensive linemen are aligned in a shaded 2 technique and a 3 technique. The shaded 2 technique implies that the defensive lineman on the left is aligned across the shoulder of the offensive lineman. To the right of the image, there is the 3 technique aligned tackle. These two techniques have been prevalent in the Patriots three preseason games and make up the Even (center uncovered) front.


Below is a different shot of the same techniques used against the Detroit Lions.

Again, a different shot of the same techniques used but it’s an entire look at the front seven. The two interior defensive linemen are lined up in shaded 2 technique (nearest interior DL) and a 3 technique (furthest interior DL). The nearest defensive end is lined up in a wide open five technique (more on that below) while the defensive end at the top of the screen is lined up in a 7 technique.


The image below shows an example of the Patriots using open end 5 technique ends to each side of the defensive line while having the nose tackle (center of defensive line) aligned in a 0 technique. The open end five techniques that are seen in the image below are similar to typical five technique (that was shown in techniques images) but the only difference being the ends are lined up wider. The Patriots have aligned their ends in this technique numerous times this preseason.


Below is an image of the Patriots’ two interior defensive linemen aligned in 3 techniques on each side of the formation. These two techniques have been used throughout the preseason. The two stand up rushers in the image are 9 (on the left, the tight end side) and 5 techniques (the right). This qualifies as an Even front along the defensive line, and this also puts the MLB (middle linebacker) in a 2 gap assignment, as he is responsible for both A gaps. This end zone shot was taken in 2008 against the Indianapolis Colts. As mentioned earlier, football is a cycle.


With that said, one must be asking themselves what this all means. What all of this means is that the Patriots defense is made up of several techniques that make up multiple fronts and allow the Patriots to slide in and out of the 3-4 and 4-3. These multiple fronts can be narrowed down to five basic fronts, which are the Even, Under, Over/Odd, Jam/Bear and Okie.  The various techniques and fronts used this preseason does not preclude the team from using a 3-4 or a 4-3 front. It enables them to, allowing them to slide and out of the  3-4 and 4-3.  The use of the Odd to Under front in particular has allowed the Patriots to slide in and out of the 3-4 and maintain their techniques and responsibilities. This is why the Patriots will not be simply a 4-3 defense. They will still be multiple and out of various packages (nickel, dime, etc.). The Patriots may run up to seventeen fronts a year under Bill Belichick in New England, and it is not likely to change this upcoming season.

Covering the Secondary

The Patriots secondary is one of the most interesting ones in the NFL. The reason it is one of the most interesting is because, like their front seven, it is flexible and multiple. The Patriots are known for using a lot of defensive backs on the field. They rely a lot on the nickel (5 defensive backs) package and because of the extra defensive back, they use more coverages. During the 2007 NFL season, the Patriots ran over 37 coverage variations. It is an astounding number and their use of various coverages has continued.

One thing that Belichick likes to do is combine coverages. By combining coverages, he presents two different types of coverage in one. For example, Belichick may mix Cover 1 (1 deep safety in zone, man coverage by cornerbacks and linebackers) and Cover 3 (3 deep zone, 4 underneath zones) to form one single coverage. By doing this, he is able to cover all parts of the field that can be threatened by the passing game while still being able to account for the run game in the box.

Another thing that Belichick likes to do is pattern read, also known as match-up zone. Pattern reading is man-to-man coverage after the distribution of routes. To put it in simpler terms, defenders are assigned landmarks to cover and once a receiving threat enters that area, the defender covers him man-to-man before passing him off to his teammate. Belichick has used this in the red zone in the past and still does today.

However, instead of breaking down 37 coverage variations in Belichick’s defense, we’re going to look at the two main coverages that Belichick teaches out of: Cover 3 and Quarters.

Cover 3 has a single high safety in zone coverage with two cornerbacks shading a wide receiver’s inside or outside shoulder in man coverage. The single high safety’s responsibility is to read the quarterback and break on the ball in hopes of getting a pass break-up or an interception. The key for the safety is to not lose leverage, thus he must keep his shoulders squared to the line of scrimmage.

The cornerbacks determine their shade based off of a divider. A divider says that if a wide receiver aligns on the numbers of the field, the cornerback aligns inside shoulder (shade) of the wide receiver. The divider also says if the wide receiver is inside the numbers, meaning between the hash and the numbers, the cornerback should align on the outside shoulder of the wide receiver. By doing this, the cornerback takes away certain routes. If the cornerback is aligned on the inside of the receiver, he is taking away any inside-breaking routes (post routes, dig routes, etc.) while aligning outside of the receiver allows the cornerback to take away any outside-breaking routes (corner routes, wheel routes, etc.).

Cover 3 also features eight in the box, meaning four pass defenders underneath. The strong safety and weak side outside linebacker (W) are required to cover any curl routes and flat routes while the two inside linebackers (M and M) are required to cover any hook patterns across the middle of the field. The landmarks of the two inside linebackers are the hash marks of the field; meanwhile the two curl/flat defenders are splitting the difference between the hash marks and the numbers on the field.


The next coverage that Belichick teaches is Quarters, also known as Cover 4. Quarters is a blend of man and zone coverage. In this coverage, there are two split field safeties (or 2 high safeties) and their job is to read the run first, then the pass. The safeties read the #2 receiver to the #1 receiver. If the #2 receiver goes deep, the safety takes him. If the #2 receiver goes outside then the safety doubles the #1 receiver with the cornerback.


The cornerbacks are in man coverage and can be either inside or outside shade on the wide receiver. In the diagram above, the cornerbacks are shown in an outside shade but it may vary depending on the coaching staff. The three underneath defenders are the linebackers, SAM (strong side), MLB (middle), WILL (weak side). The SAM and WILL linebackers are responsible for the flats. They are to carry any flat routes ran by #2 and in some situations, and they will be asked to carry vertical routes by #2 to a certain distance, such as 6 to 8 yards. The MLB is responsible for covering the middle of the field and disrupting any routes in front of him.

These are the two coverages that Bill Belichick teaches out of: Cover 3 and Quarters (also known as Cover 4). They are both able to handle vertical threats (to some degree) and play the run in the box. Bill Belichick runs over 30 variations of coverages each season and many of them are made up of combined coverages as well as pattern reading and spot dropping. These various coverages are flexible and due to the sheer amount of them, they can be disguised and ran to force quarterbacks to make the wrong reads on the field.