When I wrote about Green Bay Packers DE Cullen Jenkins earlier, I should have pointed out this excellent article on why he'll be too expensive for the Packers to keep. And due to his age (he turned 30 earlier this year) and a recent history of injuries in 2008 and 2010, there is some risk in re-signing him. But I don't think either is as big a risk for an interior defensive lineman. Defensive lineman age better than some players (it's not like it matters much if he loses a step, his game is built on strength) and he's played in all 16 games in 4 of his 7 NFL seasons.
According to Pro Football Focus, he's been one of the best interior defensive lineman at rushing the passer, coming in at No. 3 in 2010, and No. 1 over the past three seasons. Although 49ers Justin Smith has played in a lot more snaps, and recorded a lot more total pressures. From PFF:
Overall it's an interesting list of big name players, no-name players, and journeymen. Some veterans just aren't washed up when we expect them to be. Is anyone else surprised that former Packer DE Vonnie Holliday is still an effective pass rusher?