1. Mario Williams (HOU)
He has one of the oddest free-agent profiles in recent memory. He's a former first overall pick who, by most measures, matched the hype. And yet the team that drafted him has little choice but to let him test the open market. Plus he was injured last year. Plus he recently switched to a new position. The narrative is disjointed to the point that it's hard to make any sense of it. The only non-negotiable is his talent. From 2007 to 2010, Williams had the sixth-most sacks in the NFL, and all the men in front of him are at least two-and-a-half years older than he.
2. Calais Campbell (ARI)
Campbell doesn't get enough sacks to merit national media attention, but the 6'8" behemoth finds other ways to impact the game. Last year, he recorded 10 pass deflections, second among all down linemen, and led all defensive ends in Advanced NFL Stats' Win Probability Added. It's no wonder then that the Cardinals plan to tag him.
3. Robert Mathis (IND)
Mathis is a proven pass-rusher in his prime and, at face, one would think the Colts are anxious to keep him. But with the franchise's direction still unclear and the defense transitioning to a 3-4, it's hard to see where Mathis fits. One of the high-profile Colt FAs will slip through the cracks.
4. Cliff Avril (DET)
Young and on the upswing, Avril looks like a rising pass-rushing force. That was good news for the Lions last season, but bad news for their bank accounts. Detroit is straining to fit another long-term deal onto their bankroll and Avril won't settle for anything less than top dollar. Complicating matters is Avril's threat that he'll hold out if Detroit uses the franchise tag. Meanwhile, the other 31 sharks circle.
5. John Abraham (ATL)
Someone will pay him top dollar based on past production and you have to marvel at Abraham's consistency. He's posted nine or more sacks in eight of his 12 NFL seasons, including each of the last two. But he's about to turn 34 and no one in NFL history has posted double-digit sacks at that age or later. Atlanta knows that (or some derivative thereof) and looks hesitant to give him big money.
6. Jeremy Mincey (JAC)
Though it got lost in a lot of bad football, 2011 was a breakout year for Jacksonville defensive end Jeremy Mincey. The Jags leaned on him to provide pressure and he delivered, registering nine sacks and 17 quarterback hits. His play lifted a D that finished eighth against the past. At 28, he should be right in the thick of his prime years.
7. Mark Anderson (NE)
Anderson wasn't as good as teammate Andre Carter last year, but he's younger and healthier. The counterpoint: He'd been awful the four seasons prior. Teams will take note of those inconsistencies before offering big money.
8. Andre Carter (NE)
A true out-of-the-blue year from the Bill Belichick bag of tricks—or was it? Carter has now posted double-digit sack totals in each of the last three odd years, but never surpassed four in the even campaign. Hmmm... Frivolities aside, Carter put together a fabulous 2011 and appears in line for one more payday. He'll be 33 when camp starts, however, and that combined with last year's season-ending quad tear hurt his value. He wants a multi-year contract, but may have to settle for one.
9. Israel Idonije (CHI)
The recent uptick in Idonije's play coincided with the arrival of Julius Peppers, a clear indicator of the attention teams pay to Peppers. That isn't to say Idonije can't play, only to point out that he might not deliver similar numbers while riding solo.