The San Francisco 49ers suffered a fairly notable injury in the first quarter of their Week 2 contest with the Seattle Seahawks. Nose tackle Ian Williams went down with a leg injury, and has been ruled out for the rest of the game. Glenn Dorsey replaced him at nose tackle. Pro Football Talk is now saying a league source has indicated it is a broken ankle.
Williams went down on what appeared to be a legal but still potentially unnecessary run block. Williams was helped off by two trainers, and then took a cart back to the locker room. It appears he quickly got his ankle x-ray'd, and we seem to have a preliminary answer. Harbaugh will get questions about it after the game, but I imagine he won't have a lot to say.
Dorsey was signed in the offseason to compete with Williams at nose tackle. Williams won the job, but Dorsey was still in line for significant playing time as a utility lineman. Shortly after replacing Williams, Dorsey secured a sack of Russell Wilson.