The Patriots "escaped" Denver with a victory and managed to reinvent themselves on defense. After starting off as terribly on defense as they've been all season, the defense showed its versatility and resolve by making the necessary adjustments and fighting back.
The loss of Andre Carter hurts and he cannot be replaced; the Patriots will have to find a way to fix its defense to move forward without him. Of course, the Patriots only stayed in the 4-3 base defense because of Carter and his strengths. Carter was known for his historical inability to play in the 3-4 defense so head coach Bill Belichick played to Carter's strengths and was rewarded by Carter being the best player on defense. However, without Carter, the Patriots have no real reason to stay in the 4-3 front.
Of the Patriots defensive lineman, Vince Wilfork, Kyle Love, Ron Brace, Brandon Deaderick, Gerard Warren, and Shaun Ellis all have experience as 3-4 linemen. In fact, here's my proposed 2-deep lineup:
LDE: Ron Brace - Shaun Ellis
NT: Vince Wilfork - Kyle Love
RDE: Brandon Deaderick - Gerard Warren
That front will be able to contain the run between the tackles, while also being able to rush the quarterback with Deaderick. While Deaderick is not as effective as Richard Seymour, the Patriots have been moving Deaderick to defensive tackle in the 4-3 front on passing downs so Deaderick can better rush the quarterback. The Patriots are comfortable with Deaderick as a pass rusher, so he is the most likely player as the RDE.
Looking at linebacker, the Patriots have been preparing to make the defense more versatile as expected Carter-replacement Mark Anderson has been taking more and more snaps from the 3-4 Outside Linebacker spot. While the overall linebacker spot make be weak as Brandon Spikes recovers from his knee injury, the return of Dane Fletcher has greatly helped the depth. The Patriots have players who are versatile enough to help. Here's my proposed linebacker depth chart:
LOLB: Rob Ninkovich
LILB: (Brandon Spikes) - Dane Fletcher - Gary Guyton
RILB: Jerod Mayo - Tracy White
ROLB: Mark Anderson
This leaves the Patriots extremely thin at outside linebacker, but the Patriots are looking at the same formation in the 4-3 look, as Anderson takes one defensive end role, while Ninkovich plays outside linebacker. The Patriots will have more pass rushing versatility out of the 3-4 defense as either Anderson, Ninkovich, both, or neither can rush the quarterback. In the 4-3 set, the general expectation is for Anderson to rush on every snap so the opposing offensive line can set a player aside to block him. The Patriots pass rush could become more dangerous in the 3-4.
The secondary should remain unchanged from earlier in the season- however that does not mean that the pass defense will be the same. One of the main benefits from the 3-4 defense is the additional traffic the outside linebackers can add in passing lanes. You know those plays that have hurt Devin McCourty (and that lefty Tim Tebow used to exploit Kyle Arrington)? The 3-4 Outside Linebackers have the ability to drop back into those passing lanes to prevent the inside throws, while allowing the safeties to more aggressively attack the passing lanes. Here's my proposed depth chart in the secondary:
LCB: Devin McCourty
NCB: Nate Jones
SS: Pat Chung - James Ihedigbo
FS: Vincent Fuller - Sergio Brown - Matthew Slater
RCB: Kyle Arrington - Antwaun Molden
Either Fuller or Jones could play safety, but I believe that Fuller is better at safety in the base 4 DB secondary. Fuller could slide up to nickelback in the 5 DB set, but the Patriots could want to allow Fuller to slowly transition into the Patriots secondary. It's clear that the Patriots front office realized that they could not succeed in the playoffs with their safety position in its current shambles, as Sergio Brown, Matthew Slater, Nate Jones, and Sterling Moore have all rotated in and out of the role. I have the feeling that the Patriots have brought in Fuller to play safety instead of nickel back, where he spent the majority of his time in Tennessee.
The loss of Carter is huge, but the Patriots have the chance to revert their defense to a look that almost everyone on the roster is more comfortable defending. Expect the Patriots to show their hybrid defense with a mix of 3-4/4-3/3-3/4-2 fronts in order to confuse opposing offenses, while allowing the defensive players to transition to their more traditional 3-4 defense.