In speaking with reporters on Monday, Buffalo Bills right guard (and backup center) Kraig Urbik revealed that he's been diagnosed with a high ankle sprain, and has already been ruled out of the team's upcoming Week 5 matchup with the San Francisco 49ers.

Urbik was injured in the first half when a player fell onto his foot. He spent most of the rest of the half on the sidelines getting his ankle re-taped and testing out the injury with light drills, but wound up in the locker room before the halftime break and didn't return.

Now, he's likely to miss at least one game, and he could miss more beyond that, as well. Chad Rinehart will replace him in the starting lineup while he's down, and Colin Brown will assume backup center duties as the fourth active interior lineman on game days.

Bills head coach Chan Gailey later confirmed to reporters that left tackle Cordy Glenn is in the same boat: he has a high ankle sprain, and won't be suiting up against San Francisco. He'll be replaced in the starting lineup by Chris Hairston.