Attrition at tailback could become a concern for Coach Lane Kiffin

USC goes into survival mode Saturday, Coach Lane Kiffin hoping his team can get through a limited-contact scrimmage without major injury in the final workout before classes begin.

Kiffin was holding his breath Friday when senior tailback Allen Bradford went down because of an apparent knee injury. Bradford was carted out of the practice facility at the end of the workout with an ice bag wrapped around his left knee.

Bradford said later that doctors told him he suffered no ligament damage. He described it as a contusion and said he would probably participate in the scrimmage.

“We’ll see how I feel,” he said.

Bradford’s brush with a more serious setback came in the same practice senior C.J. Gable sat out because of hamstring and shin soreness.

Kiffin said he would be concerned if neither senior scrimmages today.

“That doesn’t leave a lot of people,” Kiffin said, adding, “We’ll become a spread team like Hawaii I guess.”

Kiffin was joking, of course, but he already limited the number of tailbacks available for the Sept. 2 opener at Honolulu by suspending freshman Dillon Baxter. Junior Marc Tyler and sophomore Curtis McNeal are the other tailbacks.

Robey makes move

Freshman Nickell Robey appears on track to start at cornerback opposite senior Shareece Wright.

Kiffin said the Florida native has “jumped ahead” of Torin Harris and Brian Baucham by being the most productive player in the secondary.

“He’s the front-runner right now,” Kiffin said.

USC, however, might be required to play three cornerbacks most of the game against Hawaii with Robey at the nickel spot.

Barring injury, Rhett Ellison will start at tight end.

Kiffin said starting positions still to be decided include middle linebacker, left guard and a receiver opposite Ronald Johnson.

New administrator

David M. Roberts, who this month joined USC’s administration as vice president of athletic compliance, attended practice.

“It’s a new day, and the things we’re doing out here now should show the NCAA we understand what they’ve said,” Roberts said. “We may not agree with everything they’ve said, but we understand it. We’ve taken the actions that they want to have taken and, quite frankly, I think everybody I’ve spoken with from the athletic department to administration understands we want to compete honestly within the rules and at the highest level.”

Quick hits

Freshman quarterback Jesse Scroggins and freshman safety Demetrius Wright can no longer practice until they are certified by the NCAA Eligibility Center, Kiffin said. Signee Soma Vainuku’s academic eligibility issues might prevent him from enrolling until spring, Kiffin said. . . . Quarterback Mitch Mustain spent the morning workout rolling on the turf and doing punitive calisthenics. “Just late,” he said after practicing in the afternoon. “That’s all I’m saying about it.” . . . Kiffin said receiver David Ausberry, who caught three touchdown passes in the first two scrimmages, was not practicing because of symptoms similar to those he experienced last season when he sat out six games because of a stress fracture.

gary.klein@latimes.com