Posted by ESPN.com's Ted Miller
USC's Kristofer O'Dowd, widely regarded as the No. 1 center in the nation, dislocated his right kneecap during a scrimmage Monday. It's unclear how long he will be out, but he missed four games as a freshman with the same injury.
He will undergo further tests on Tuesday.
The USC offensive line welcomed back all five starters, and eight players have seen significant action. Senior Alex Parsons is O'Dowd's likely replacement, though senior guard Jeff Byers could shuffle inside.