Today, Chris Clemons was officially placed on injured reserve, a move that should surprise no one after Clemons tore his ACL against the Redskins last Sunday. Somewhat more surprising was the announcement that Steven Hauschka was also put on IR, which means Ryan Longwell will be the Seahawks' kicker for the duration of the playoffs.
To fill the empty spot on the roster, DE Patrick Chukwurah was signed off the street today. Chukwurah played for three NFL teams from 2001 to 2007 mainly as a special teamer, although he did manage to rack up nine sacks in limited defensive snaps Since then, he's worked as a personal trainer and played two seasons in the UFL. I've read a few reports that say Chukwurah led the UFL in sacks during those seasons, but that's hard to verify since the league doesn't seem to keep an official stat book of any sort (and possibly never will, since they suspended operations halfway through their 2012 season).
I know signing a 33 year old pass rusher who's five years removed from his last NFL action isn't the most thrilling move, but the pickings are slim this time of year. According to Ian Rapaport of NFL.com, the Seahawks also brought in Aaron Maybin, Ray Edwards, and Travis LaBoy for tryouts, so at the very least we know Pete Carroll thinks he's a better choice (or at least a better fit) than those three guys.
ADDENDUM (12:56): Chukwurah was on the Buccaneers' roster in 2008, but only briefly. He spent about three or four days with Tampa Bay in late August before being released, then was signed again for the last two weeks of the season. He didn't appear in any games.