Scrimmage sets scene for duel

USC Coach Pete Carroll moved today’s scrimmage at the Coliseum from the afternoon to evening, partly to infuse the Trojans with a sense of excitement.

The change probably was not necessary to energize Aaron Corp and Mitch Mustain.

The two quarterbacks know an outstanding individual performance could turn their competition to possibly replace injured starter Mark Sanchez for the Aug. 30 opener at Virginia.

“It’s a race to see who can take over,” Carroll said Friday.

Playing behind an inexperienced line and with mostly reserve receivers, Corp and Mustain both had good moments in the Trojans’ first scrimmage Tuesday.

But each turned the ball over inside the 20-yard line, and neither led the offense to a touchdown or field goal.

Carroll said starters would play more tonight.

Corp got most of the first-unit snaps in the first scrimmage, an opportunity Mustain hopes to receive.

“I don’t think it will be a make-or-break deal,” Mustain said of the effect an outstanding performance could have on his chances, “but I certainly think it will help.”

If Sanchez is not available for the opener, Carroll said he would not go into the Virginia game planning to use both Corp and Mustain.

“But if the competition is really close, I wouldn’t hesitate to go with the other guy if things aren’t working right,” Carroll said.

That scenario could become moot if Sanchez returns. A week after dislocating his left kneecap, the junior continues his rehabilitation.

On Friday, he moved more fluidly on the sideline and while dropping back to throw easy passes.

“I bet you sometime in the middle of next week he’ll be doing stuff,” Carroll said.

Veteran presence

Offensive lineman Jeff Byers finally participated in full-contact work in the afternoon practice, lining up with the first unit.

The fifth-year senior is expected to start at left guard and anchor a line that is largely young and inexperienced.

“It was a good day for me,” Byers said. “I was a little rusty, a couple days behind. About 12.”

Byers had been sidelined by flu-like symptoms and an enlarged spleen, with his condition diagnosed as Rocky Mountain spotted fever. His spleen gradually recovered to the point where he was cleared to play.

“We really enjoy his experience because we are such a young group,” Carroll said.

The underclassmen have struggled at times, blowing assignments, bumping into each other while offensive line coach Pat Ruel screamed and Byers stood on the sideline.

“It’s always hard to watch,” Byers said. “You want to be out there helping them, making sure guys are doing the right thing.”

He might get a chance to settle things down at tonight’s scrimmage. Given that the offense struggled in Tuesday’s scrimmage, he said, “We’ve got to execute.”

“It doesn’t hurt that our defense is pretty dang good,” he said. “But that’s no excuse. We’ve got to go out and play well.”

Quick kicks

The scrimmage at the Coliseum, originally scheduled for 4 p.m., was changed to 7 p.m.

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gary.klein@latimes.com

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