4-3 or Bust? The New England Patriots and Their New-Look Defense

Much has been made of the Patriots surprising switch to the 4-3 defense in their first pre-season game against the Philadelphia Eagles.

After displaying a four-man front almost exclusively in the first game, I went back and looked at the tape of their second game against the Bengals in order to decipher what kind of defense they'll ultimately run this season—and what it might mean for an old war horse suddenly finding himself without a position to play.

Looking at the first half of the game, when most of the Patriots and Bengals starters remained in the game, the Patriots switched between the 3-4 and the 4-3, sometimes within the same series.

Here's the breakdown:

First Bengals possession: 12 plays, with just three down linemen in 10 of them

Second Bengals possession: five plays, all but one run with three down linemen

Third Bengals possession: 10 plays, all run from the 4-3 base

Fourth Bengals possession: one play, run out of the 4-3 resulting in a forced fumble

Fifth Bengals possession: four plays, three in 4-3 with one 3-4

Sixth Bengals possession: nine plays, one from the nickel, six out of the 4-3 and two from the 3-4.

So for the first half, the Patriots lined up 41 times and basically were split down the middle with a three-man front 17 times and a four-man front 23 times (they just had two down linemen in the one play they ran from a sub-package on a long third down).

What does this tell us? Well, it shows a remarkable amount of flexibility among the front seven of the Patriots. The ability to switch so quickly is remarkable, especially with guys who are younger and just beginning to learn the defense.

On the last drive of the half by the Bengals, in particular, the Patriots showed their ability to switch it up. They ran with a four-man front the first three plays then over the next four plays switched back and forth from three down linemen to four.

On the surface, there doesn't appear to be a whole lot different between the 4-3 and the 3-4. Just an extra guy with his hand on the ground, right?

Well, that's true, to a point. The big difference comes from the personnel grouping that the Patriots are capable of using in each system.

The Patriots run two different types of 4-3. One is much heavier, with the Patriots able to line up four 300+ pound linemen who all are adept at getting after the quarterback while stuffing the run and soaking up double teams.

The other 4-3 alignment is much more bent on getting after the passer and will likely involve the normal three down linemen with Derrick Burgess also getting his hand dirty before rushing.

So far, the 4-3 has been pretty successful in the first two pre-season games. The Patriots were largely able to contain the Eagles and Bengals with their starters in, although the secondary (Terrence Wheatley in particular) was victimized by the Bengals' receivers.

The switch was still quite a surprise though coming into the season. As a half dozen teams have joined the trend and made the 3-4 their base defense, Belichick is going the exact opposite direction.

Still, when you look at the Patriots' moves this off-season, the personnel they have under contract, and the guys they have to re-sign in the near future, their motives become a little clearer.

First, lets look at the Patriots draft. With Vince Wilfork eventually holding out of "voluntary" organized team activities, the fact that the team drafted three defensive tackles was seen largely as a "just in case" move to cover the team if Wilfork either held out into the season or refused the team's contract offers after this season.

However, with the 4-3 now looking like it'll be a common sight this year in New England, picking up some extra defensive tackles makes a lot more sense.

But the biggest effect the change may have—and the one that will probably surprise New England fans the most—may regard Tedy Bruschi's future.

Even coming out in the 3-4, Bruschi didn't play much in the first half, only entering the game with the backups. With four linebackers, Bruschi has less ground to cover, but he's not as young as he used to be.

Also, there's just not much behind him in terms of inside linebacker talent. Gary Guyton is his immediate backup, but that's about it for depth. It sounds simple, but with far greater depth along the defensive front the 4-3 just plays to their strengths more.

In the 4-3, Jerod Mayo is the clear choice starter at middle linebacker, especially as evidenced by Belichick's decision to give him the defensive radio.

Bill claimed it was by virtue of his position in the middle of the field, but in a 3-4 the more veteran Bruschi would've also been in the same position.

Personally, I think Belichick believes Mayo is ready for some more responsibility, and Bruschi may have to split time with Gary Guyton.

Moving to the 4-3 also opens up the team's options concerning Richard Seymour and Vince Wilfork.

It'll be difficult for the team to re-sign both players, but by moving away from the 3-4, where a big, hulking nose tackle is essential, the team certainly gives itself a little more leverage in their future negotiations with Wilfork.

So what will the defense look like come Week 1?

Right now, they've played one game almost exclusively in a 4-3 and began the Bengals came in the more familiar 3-4, so it's hard to know exactly what they'll end up doing.

I think it'll be a hybrid, showing both alignments to opposing offenses as down, distance, and personnel requires.

Whatever happens they'll have to shore up the fundamental problems they had last season, especially on third down, no matter how many men are on the field.