Over the past few seasons, the New England Patriots have taken some interesting and necessary steps to evolve their base defensive scheme. They will always be a multiple-front defense, but they've certainly shifted some of their personnel philosophy especially for their base, run-stopping defense.
After 2012, it's clear the changes have worked in some areas, but more adjustments are still needed this coming offseason.
In the last decade, Bill Belichick's Patriots were primarily built as a Fairbanks-Bullough 3-4 defense, but as passing offenses in the NFL have exploded, a passive read-and-react scheme was easily exploitable.
In 2011, they shifted away from the 3-4 front as their base defense and went to more of a 4-3, albeit with Belichick's unique twist. Instead of Vince Wilfork serving as a traditional nose tackle, he became their primary defensive chess piece, and they moved him wherever they saw the best matchup.
Many of the concepts of the Fairbanks-Bullough remained but only in select spots. They will still two-gap in this 4-3, whereas more traditional ones go with more of a "stop the run on the way to the quarterback" philosophy.
The switch to the four-man front was also necessitated by the lockout-shortened offseason, as the 4-3 scheme was easier to find personnel for.
Despite the scheme change, the Patriots defense continued to decline in all areas of Football Outsiders' DVOA metrics from 2010 to 2011. Instead of 32nd in third-down defense, they were 28th.
So in 2012 they again tweaked the base defense by switching Rob Ninkovich to left defensive end from strong-side linebacker. At 6'2" and 260 pounds, Ninkovich is lighter than the player the Patriots traditionally liked in the spot, with Ty Warren being the model at 6'5" and 300 pounds.
While the difference between outside linebacker and defensive end is somewhat just semantics, the 2012 defense was, in essence, two down linemen and five linebacker types. Or a "Double Nose" 4-3, as it featured two defensive tackles who would be traditional nose tackles in the 3-4.
The problem with nose tackles is that it's hard to find ones who can push the pocket with any consistency, and the Patriots' early-down pass defense has struggled because of it.
The biggest concern before the 2012 season was whether their run defense would hold up with a lighter player like Ninkovich playing on the line, but ironically the move actually improved their DVOA dramatically from 25th to sixth.
The problem remained the pass defense, even with a pretty good pass-rusher in Ninkovich holding up well against the run. It also allowed them to remain in their base defense without wholesale personnel changes from down to down, as was the case in 2009.
The Patriots did improve on defense across the board in 2012, according to Football Outsider's metrics. However, what needs to be done to fix the continuing problems with the pass defense on early downs, when they're most often in their base defense?
Brandon Spikes, while a dominating run-stopper, does not have the quickness required to cover the tight ends in the flat, especially when the Patriots played Cover Two Man, which they often did in 2012.
Spikes had a breakout year, but it's not a coincidence the Patriots have been near the bottom of the NFL in covering slot receivers and tight ends the last two years he's started.
The Patriots have been eaten alive over the middle of the field.
With the 3-4 defense, the weak inside linebacker like Tedy Bruschi would also be present to defend the middle of the field. But in the 4-3, it's just the middle linebacker—if he's not agile in coverage, the defense will be exposed.
Spikes is a valued and ferocious presence in the middle of the Patriots defense, but Dane Fletcher and any other coverage linebacker the Patriots bring in should be given every chance to show they can be as big of an asset against the pass as Spikes is against the run.
Dont'a Hightower does move a little better than Spikes, so perhaps they should consider sliding him to middle linebacker and then re-evaluate the stong-side linebacker position and potentially add more coverage ability there as well.
Is it time to acknowledge that Spikes might just be a run-stopping role player, unless his coverage skills dramatically improve in the offseason?
The Tackle Next to Wilfork
Kyle Love and Brandon Deaderick both saw time as the starting defensive tackle not named Big Vince this season, but they recorded just three sacks combined. In today's NFL, that's not going to cut it. Neither player is as talented as Wilfork, and both would be better suited in a two-gap 3-4 defense.
The Patriots shifted to more of a traditional 4-3 end in Ninkovich this year, so why not switch to a more traditional 4-3 defensive tackle next to Wilfork? They might give up something in run defense with such a player, but it's not the run defense that is lighting them up in the middle of the field.
The defensive tackles have the shortest path to the quarterback, so a real get-upfield disruptor would have a positive impact against quick passes to the flat on early downs.
Having someone to work off like that would also do wonders for Chandler Jones.
Building Around the Foundation
Mayo, Wilfork, Jones and Ninkovich are the four key pieces to the 2013 front seven, but the other three spots must be closely re-examined to improve the pass defense, especially on early downs, but definitely on third down as well.
The Patriots have shown good flexibility by evolving their defensive scheme in recent seasons. While there are still concerns with their passive, bend-don't-break defensive play-calling, some final adjustments should put their pass defense over the top and set the fourth-youngest defense in the NFL up for sustained greatness.