Freshman Matt Barkley is expected to regain his status as starter when he is healthy, the source said. Barkley continues to experience pain in his bruised right (throwing) shoulder, which was injured in the third-ranked Trojans' 18-15 victory at Ohio State last weekend.
Barkley did throw during Trojans' walkthrough practice at Husky Stadium on Friday evening and USC coach Pete Carroll isn't ruling him out.
"He threw the best he has all week," said Carroll, who said he hasn't made a decision on who will be the starter.
All-American safety Taylor Mays was moving around for the second consecutive practice but continues to rest a sprained knee ligament. The Seattle native plans to suit up Saturday, though Carroll said Mays also may not find out whether he's playing until kickoff.
"That's when you are going to know who is going to be starting," Carroll said of both quarterback and safety.
Corp, a junior, took all the snaps with the first-team offense Thursday. Carroll has said if Barkley wasn't "100 percent" healthy, Corp would make his first college start. The redshirt sophomore was the starter coming out of spring camp, then he broke his leg and Barkley wowed Carroll.
"I'm preparing like I'm going to be the starter. It feels good to be back in that position," said Corp, who last started in 2006 as a high school All-American at Orange (Calif.) Lutheran. "[This week] is my chance to show off."
ESPN reporter Shelley Smith and The Associated Press contributed to this story.