Mitch Mustain is poised to start for USC for the first time Saturday against Notre Dame if Matt Barkley is not sufficiently recovered from a high- ankle sprain suffered against Oregon State.
Coach Lane Kiffin said Sunday that X-rays of Barkley's left ankle were negative and that he was "extremely hopeful" that the sophomore would be able to play.
If he can't, Mustain would start a game for the first time since 2006, when he started eight games for Arkansas.
Mustain played the second half of USC's 36-7 loss Saturday at Corvallis, Ore. The senior completed eight of 17 passes for 60 yards, without an interception. Mustain lost a fumble when he was sacked.
"He has played well for us in scrimmages since we've been here, so we look for him to play a lot better than he did Saturday if he's the guy," Kiffin said.
Walk-on John Manoogian would be the No. 2 quarterback if Barkley cannot play. Freshman Jesse Scroggins is a redshirt this season.
Barkley was injured just before halftime when he was sacked by tackle Kevin Frahm. Barkley had completed 10 of 19 passes for 75 yards, with an interception that was returned for a touchdown.
"He didn't play very well," Kiffin said. "We made it look a lot worse by the way we played around him."
Kiffin said after reviewing film that he was "completely embarrassed" by the offense's performance. USC gained only 255 yards and converted only four of 16 third downs and two of six fourth downs.
"There [are] things on that film that I don't even know where they came from," Kiffin said. "[It] doesn't look like these kids have ever been coached."
Senior tailback C.J. Gable, who had 57 yards and a touchdown in 10 carries, was "maybe the only positive on offense," Kiffin said. … Linebacker Chris Galippo will probably be held out of practices early in the week because of a concussion, Kiffin said. … USC compliance officials did not meet with players Sunday, but Kiffin said the situation involving tailback Dillon Baxter and the ride he accepted on a golf cart from a sports agent would probably move forward with NCAA offices reopening Monday. … Kiffin praised Oregon State tackle Stephen Paea, who forced a fumble and had 2½ tackles for losses. "It was like [Warren] Sapp in his heyday," Kiffin said. "He completely dominated us that entire game."