This will be the third consecutive contest that Thurmond has missed due to this particular injury. The 25-year-old cover man was able to participate in Thursday's practice in a limited fashion but he must have encountered a setback as he was forced to sit out again Friday.
According to Danny O'Neil of the Seattle Times, head coach Pete Carroll "was not optimistic" that Thurmond would be able to play in the first round of the playoffs if the Seahawks are unable to steal a first-round bye.
Tackle Breno Giacomini (elbow) and outside linebacker Leroy Hill (hamstring) also each have a chance of missing Sunday's game after being listed as questionable. Giacomini seems to be the likelier of the two to play after getting a full practice in Friday.
As for the rest of the injury report, DE Red Bryant (foot), RB Marshawn Lynch (back), TE Anthony McCoy (back), WR Sidney Rice (knee), WR Golden Tate (illness), FS Earl Thomas (ankle) and CB Marcus Trufant (hamstring) were all listed as probable and are expected to play.