USC lost to Washington last week. In this loss they were missing two key players. Safety Taylor Mays (knee) missed the first game of his career, and as we all know QB Matt Barkley was out due to a shoulder injury.
The good news is that both of these guys are both expected back this week. The maybe factor is in play though, Barkley said that he was lacking "zip" on his throws and Mays has not been cleared to run laterally as of yet. This could all clear up in the next couple of days, but I don't think it will matter because their next game is against Washington State, and they stink.
You should still look to see a heavy dose of Joe McKight and I'm sure Mays will be taking plays off to rest. USC needs both these guys healthy if they expect to win out.