LOS ANGELES — Although USC has lost two of its past three visits to Oregon State, Trojans coach Pete Carroll insists it had nothing to do with the weather, the atmosphere or any other extraneous factor.

"It's about what happens in the game," Carroll said Tuesday after USC's final full practice before Thursday night's game in Corvallis.

In their most recent trip there a 33-31 setback the Trojans fumbled three times and allowed a punt return for a touchdown.

The returner, Sammie Stroughter, has made a more significant return since then.

Stroughter missed most of last season because of a kidney injury. He also fought a long, difficult battle with depression.

He overcame both and has come back bigger, stronger and faster, according to Oregon State coach Mike Riley.

"It's very good to have Sammie back," Riley said. "It's more than obvious, as a player, that he brings a ton to the Beavers."

Stroughter is Oregon State's second-leading receiver with 21 catches, three of which have gone for touchdowns. He averages 12.1 yards per punt return, tied for second in the Pac-10.

"He hurt us two years ago. We're very aware of who he is," USC safety Taylor Mays said. "It's hard to stop guys like that. You just try to contain him and make him play within what our defense is trying to do."

With Stroughter back in the lineup, the Beavers rank first in the Pac-10 with 307.3 passing yards per game. The Trojans allow 145.5 per game.

BACKUP PLAN

Although Garrett Green would be the first quarterback off the bench if Mark Sanchez were to get hurt, that wouldn't necessarily be the case if Sanchez suffered a long-term injury.

"If Mark got banged up and couldn't go for a month or something like that, we'd look at the situation a little differently," Carroll said.

For the time being, Green would provide the most continuity as an in-game sub. Green surpassed Aaron Corp and Mitch Mustain because of a superior knowledge of the offense. Green has an additional year's worth of experience in the system, although he spent a lot of that time playing receiver and safety.

"It's tough," Green said. "The guys who are able to get in and play early, their freshman year, they're few and far between. It took a while, and everything I've learned up until this point over the last two and a half years has helped me get to the point where I'm at now."

Corp (Orange Lutheran) said he performed poorly during USC's bye-week practices, and the coaches noticed.

"They're holding true to their word: They're going to put the best guy in at the time," Corp said.

"You just have to work that much harder."

KICK-START

USC practiced on FieldTurf on Tuesday to prepare for Oregon State's playing surface, but kicker David Buehler got a head start. Buehler and the other specialists worked on the track-stadium infield on Sunday and Monday. He said he kicked about 40 field goals over those two days.

"I actually like playing on FieldTurf better," Buehler said. "With grass you have to pick your spots, and sometimes there's little divots from guys making cuts. You can't put the ball in a divot. That'll mess you up. The whole surface is the same (with FieldTurf)."