Two parts of USC's quarterback equation became almost certain when Mark Sanchez returned last week from a knee injury.
Sanchez would start Saturday's opener at Virginia. And redshirt freshman Aaron Corp, who started the Trojans' final scrimmage and took the majority of leftover snaps upon Sanchez's return, would back him up.
"I've heard it's one of the toughest positions in sports -- you have to keep preparing like you're going to play," Corp said Wednesday.
Corp beat out Arkansas transfer Mitch Mustain for the back-up role against Virginia by demonstrating a better command of the offense.
The mobile Corp began making a move toward the end of spring practice and continued his ascent after Sanchez suffered a dislocated kneecap Aug. 8.
Coaches quietly informed Corp and Mustain of their status a few days ago, but the competition will continue, Coach Pete Carroll said.
"They've been dead-even the whole time and we'll see what happens," Carroll said. "The edge that anybody would have over either one of them right now is not very significant. We just have to pick out somebody that's going to go next."
Mustain stoically cited Corp's improvement during training camp but would not concede that Corp's status was permanent.
"I certainly don't think it's set in stone," he said.
Asked whether he regretted his decision to transfer to USC, Mustain said, "No, not at all. I still have three years. That's a lot of time for a lot of things to happen."
Sophomore tailback C.J. Gable said this season's team is a closer group than the 2007 Trojans, who featured 10 players selected in the NFL draft but fell short of playing for the Bowl Championship Series title.
"It had a lot of egos," Gable said of the 2007 team. "People were just trying to hurry up to leave and get out of here.
"This year we have a goal to go undefeated and get better . . . so as a team we're all doing our part."
Cornerback Shareece Wright (abdomen) completed practice for the first time this week and said he would play against Virginia. . . . The Trojans practice this morning and leave for Charlottesville, Va., in the afternoon.
Saturday, 12:30 p.m., Channel 7