Overview: Patrick Kerney played in seven games before a torn labrum in his left shoulder ended his season. It was the second labrum tear in his left shoulder in less than a year. He's also had surgery on his wrist and surgery to remove bone chips from his elbow. He had five sacks in his seven games.
What went right: Seattle's defensive line declined, especially at rushing the passer, and despite a less capable Rocky Bernard and playing across the line from the ineffectual Lawrence Jackson, Kerney set a pace for double digit sacks. He showed pretty good speed around the edge and kept himself in plays by moving his feet and working his hands. His essential pass rush repertoire was intact: The first step, the push to separate, the equally capable inside and outside burst, and the inside rip.
What went wrong: He still wasn't as good as he was in 2007. He had more sacks through seven, but he was less disruptive. He was severely injured and lost most of his age 31 season. He turned 32 last December.
Outlook: Kerney ranks 50th all-time for career sacks. 28 defensive ends that played through their age 32 season rank ahead of him. It's a group you would expect to play well late into their career, and they did. They averaged 10 sacks in their age 30 season and 13 finished with double digit sacks. They averaged 9.8 sacks in their age 31 season and 18 finished with double digit sacks. 32 is the first big drop*. They averaged just 7.3 sacks and only eight finished with double digit sacks. Four of those eight are in the top five for career sacks, and those four represent 54.5 of the 204.5 sacks accredited to the group. The remaining 24 averaged 6.3 sacks. Kerney is not Bruce Smith, Reggie White or Michael Strahan, but maybe he can be Chris Doleman. Doleman's unheralded but fantastic career had definite peaks and valleys. He had 27 sacks at 31 and 32, just 16 at 33 and 34, but then 38 at 35, 36 and 37. Doleman was never severely injured. Kerney's got about as bad a bunch of injuries as a defensive lineman can have without losing his back or knees.
I don't expect a precipitous drop, though it's happened to better ends than Kerney, but anything approaching his 2007 is far fetched. If he's healthy, Kerney is likely good for five to nine sacks. He could be worse, he could be hurt still or hurt again, but he's very unlikely to be much better. It is much more likely Kerney gets less than five sacks than more than ten sacks in 2009. After 2009, the team better figure out a replacement and fast.
*One might say, for an acceleration dependent position like defensive end, 32 is like a running back's age 30.