Two knee injuries, two recoveries.
For the second time this season, USC quarterback Mark Sanchez has shaken off a knee injury to remain in the starting lineup for the eighth-ranked Trojans.
Sanchez, who overcame a dislocated left kneecap in training camp, showed what is becoming trademark resilience Thursday by completing a full practice five days after suffering a bone bruise in the same knee against Oregon.
Barring a setback, Sanchez will start on Saturday against Arizona State in a Pacific 10 Conference game at the Coliseum.
"It looks like that's the way it's going," Coach Pete Carroll said.
Sanchez has passed for 13 touchdowns with three interceptions. He is ranked seventh nationally in passing efficiency with a 172.2 rating.
Last week against Oregon, Sanchez was 19 of 28 for 332 yards and three touchdowns. He missed a series after being injured on a third-quarter sack but returned and played into the fourth quarter.
Sanchez's status for Arizona State, however, was doubtful early in the week.
"He's gotten better as the days have gone on so if that stays on course he should be fine," offensive coordinator Steve Sarkisian said.
Mitch Mustain will back up Sanchez for the second consecutive game.
Johnson catching on
Junior Stafon Johnson will return punts against Arizona State, supplanting sophomore Joe McKnight, who has struggled with fumbling.
Johnson had an 18-yard return against Oregon after replacing McKnight.
Carroll said Johnson "had had a steady game last week and we want to make sure Joe's focused on his stuff and doesn't have to be concerned with that right now."
Johnson is expected to shoulder an increased workload at tailback against Arizona State, but he welcomes the opportunity to do even more.
"I was built for this -- I worked hard in the off-season just in case something like this would come about," Johnson said. "I didn't want stamina to be an excuse not to do it."
Arizona State quarterback Rudy Carpenter, who suffered an ankle injury against California, worked with the Sun Devils' second-unit offense after sitting out Tuesday and Wednesday, according to a report on the Arizona Republic's website.
Danny Sullivan remains on track to start, but Coach Dennis Erickson said of Carpenter: "I'd be surprised if he can play, but I'm not ruling it out."
Neither is Carpenter.
"I said Monday I had to get 10 to 15 percent better every day," he said. "It's been on that track. Now we've got two more days."
Fullback Stanley Havili (neck) did not participate in contact drills but said he would play Saturday. . . . Ryan Davidson, a teenager from Wisconsin who developed close ties to USC's football program in 2004 during his continuing battle with cancer, attended practice. Davidson and his family also will attend Saturday's game. "He's just an amazing spirit and we're lucky he's kind of fallen in love with the Trojans and been with us over the years," Carroll said.