If Clifton is unable to play against the Rams Sunday in St. Louis, he will be replaced by Daryn Colledge, McCarthy said.
"He probably won't practice until Friday," said McCarthy of Clifton. "But I think he'll be ready to go this week."
Colledge lost his starting job at left guard to Jason Spitz last week. A second-year pro, Colledge is a little more suited to play tackle. He has been Clifton's backup since last season.
In other injury news, linebacker Nick Barnett saw an eye specialist Monday after being poked in the eye. He believes the Raiders' Jeremy Newberry did it on purpose. McCarthy said he didn't see it on the game tape and will let the league handle the matter.