by Sean McCormick

Buffalo Bills

Biggest Offseason Hole: Defensive End

The flirtation with the 3-4 defense lasted barely a year, just long enough to get defensive coordinator George Edwards fired, and now the team will turn to new hire Dave Wannstadt to undo the experiment and bring back a base 4-3. The move makes perfect sense, as it allows the Bills to line up their two best players, Kyle Williams and Marcell Dareus, side-by-side. That should give them the freedom to penetrate and make plays rather than requiring them to hold their ground and soak up blockers as they would in a 3-4. It's a move that should help stiffen up the interior run defense, which gave up 4.52 yards per carry on runs between the guards last year. The move probably won’t do much to generate more pass rush, however, as it is unreasonable to ask for Dareus to improve much upon his rookie total of 5.5 sacks. An elite pass rushing defensive end would be a key addition for Buffalo. The Bills have youngsters like Alex Carrington and veterans like Chris Kelsay and Dwan Edwards, but none of them can be expected to suddenly morph into a double-digit sack threat. There is little doubt that the team will make every effort to address the position, but they are unlikely to land a premiere talent like Mario Williams in free agency, so improvement may have to come from the draft.

The other major priority is to re-sign Stevie Johnson, who established himself as a legitimate number one receiver in his first year as a starter. The team will want to add another receiver regardless, as neither David Nelson nor Donald Jones showed much playmaking ability, but receiver would turn into a gaping hole should Johnson skip town.

Miami Dolphins

Biggest Offseason Holes: Quarterback, Right Tackle

Matt Moore won six of his twelve starts and was instrumental in Miami’s second-half turnaround, but all indications are that neither general manager Jeff Ireland nor new head coach Joe Philbin consider him anything more than a stopgap solution at quarterback. Instead, the Dolphins are expected to make a run at a premiere quarterback, with Peyton Manning sitting at the top of the list. If Manning spurns them, the Dolphins would likely target Green Bay’s Matt Flynn or look to trade up to the top of the draft for Baylor phenom Robert Griffin III. Whoever ends up as the quarterback, the Dolphins will need to do a better job of protecting him, as the offensive line’s 9.6 percent Adjusted Sack Rate was among the worst in the league in 2011. Some of that can be attributed to injuries, and the return of a healthy Jake Long will go a long way towards solidifying the line. However, right tackle Marc Colombo was a disaster and will not be re-signed, leaving a hole that may not be filled until the draft. Several early mocks have linked standout Iowa tackle Reily Reiff to Miami, but that option looks much more attractive with Manning or Flynn safely under contract.

Miami’s short-yardage woes can partly be linked to that same patchwork offensive line, but they also speak to the disappointing play of rookie Daniel Thomas. No one should be shocked when Reggie Bush puts up a 37 percent Success Rate, but Thomas, who was brought in to be a between the tackles power runner, was not much better. Thomas’ rushing DYAR was the worst of any running back this season, and while the team remains optimistic about his future, it might be wise to draft a potential alternative in the middle rounds.

New England Patriots

Biggest Offseason Hole: Cornerback

You don’t need advanced stats to figure out that the Patriots had serious defensive problems in 2011. The Patriots gave up 411 yards per game, allowing a league-worst average of 37.5 yards per drive. They were 28th in DVOA against the run and 28th against the pass. There is no defensive position group on the team that would not benefit from the addition of a top free agent or high draft choice, but the first order of business is likely going to be to improve the depth and talent at cornerback. The switch of Devin McCourty to free safety and Sterling Moore to corner worked like a charm in December and January, but it would be foolhardy to rely on Moore holding up for a full season without preparing a plan B. Meanwhile, top corner Kyle Arrington’s seven interceptions obscured a concerning drop in his performance during the second half of the season. Based on Football Outsiders game charting, Arrington allowed 7.2 yards per pass through the first eight games of the season, then 10.2 yards per pass afterwards (including the postseason). 2011 second-rounder Ras-I Dowling will be back from an injury that cost him most of his rookie year, but in today's NFL, a good defense needs three starting-quality cornerbacks. Bill Belichick does a much better job of throwing together a damage control party in the secondary than he does drafting long-term solutions, but the Pats probably need to take another run at the latest crop of college corners.

The pass rush was adequate, but the rotation might look different in 2012. Rob Ninkovich’s late-season development was encouraging, and he looked borderline dominant coming off the edge in the Super Bowl against an overmatched Kareem McKenzie. Mark Anderson and Andre Carter were also effective, but their contracts are up and the team may only look to re-sign one of them. Until Wes Welker gets a new deal, all other contracts will remain on the back burner.

New York Jets

Biggest Offseason Hole: Right Tackle

With the hiring of Tony Sparano as offensive coordinator to replace the departed Brian Schottenheimer, the Jets are signaling their intention to return to the ground-and-pound formula that served them so well in 2009 and 2010. That’s fine in theory, but it will only work if the offensive line rebounds after a somewhat disappointing year. While D’Brickashaw Ferguson got a Pro Bowl nod, he had a subpar year in pass protection and was dreadful in the run game -- New York backs averaged only 2.89 yards per carry when running behind left tackle, worse than every team save Tampa Bay. Ferguson’s struggles went relatively unnoticed, however, because of Wayne Hunter’s spectacular meltdown on the other side of the line. Hunter was charged with 8.5 sacks and 11 penalties according to ESPN New York, and his inability to handle the outside rush essentially took every deep pass out of the playbook. An upgrade here is a necessity. Better blocking out of the tight ends would also help New York re-establish its running attack. Dustin Keller is a one-dimensional pass catcher who gets manhandled when asked to be an in-line blocker, but reserve tight end Matthew Mulligan gave up three sacks and multiple pressures, making him the rare backup tight end to achieve notoriety with the hometown fans. In an ideal world, the Jets would land a tight end who could play all three downs and was effective when lining up in-line or splitting out wide.

The Jets also need some help stopping opposing tight ends. While the pass defense finished the year ranked second in DVOA, safeties Eric Smith and Brodney Pool struggled badly in man coverage, and teams were able to move the chains on third down by setting up isolations that left Pool or Smith matched up on a tight end. No one is better at shutting down outside receivers than the Jets, but that won’t help them close the ground on divisional rival New England. The tight end duo of Rob Gronkowski and Aaron Hernandez dominated New York both times they played the Patriots.

(This article previously appeared at ESPN Insider.)