USC has notified Penn State of its interest in running back Silas Redd, a source told ESPN's Joe Schad on Monday.

The NCAA hit Penn State with a $60 million sanction, a four-year football postseason ban and forced the program to vacate all wins dating to 1998. Penn State players are free to transfer without having to sit out. Redd is being told by coaches at various programs that he can play right away. Interested schools, however, must notify Penn State first per NCAA rules.

Redd has met with Penn State coach Bill O'Brien, who sources say has stressed to players that they can still play games and still appear on television.

Some players have concerns about if their teammates will leave and the Nittany Lions' ability to continue to field a winning team, one source said.

Redd, a 5-foot-10, 209-pound junior, ran for 1,241 yards and seven touchdowns last season. He has two years of eligibility remaining.

USC coach Lane Kiffin would not comment on Redd specifically Tuesday during the Pac-12's media day. But Kiffin acknowledged that the Trojans could use help in the backfield.

"Our No. 1 concern is our running back depth," Kiffin said. "We really have to do a good job there developing depth."

Kiffin said he and his staff would need to analyze what any additions would mean to the program, both this season and going forward.

"Yeah, you gotta look at the whole picture and figure the whole thing out," Kiffin told ESPNLosAngeles.com on Tuesday. "We're obviously in a different situation because of limited scholarships.

"We're not gonna give out any details on it, but, yeah, we've looked at everything."

At that point, Kiffin was operating on the belief that the NCAA would allow USC to go over the 75-man scholarship restriction to sign a transfer from Penn State. But, hours later, it was announced that that the Trojans would in fact not be allowed to exceed the limit because of their continuing probation.

Other schools around the country can go over their 85-man limit, but USC cannot. Therefore, in order to actually sign Redd, the Trojans would have to have one of their current players or signees become academically ineligible for the 2012 season, or take a current player from the roster off of a scholarship.

Trojans quarterback Matt Barkley told ESPNLosAngeles.com that he trusts Kiffin and the coaching staff to make the right decision as it applies to the team's chemistry.

The Trojans' captain for a third consecutive season, Barkley also said he would be willing to welcome new teammates.

"I guess it all depends on how well they adapt to USC, but I'm sure our coaching staff is concerned with all that stuff," Barkley told ESPNLosAngeles.com. "They know what the right fit our team would be."

Information from ESPNLosAngeles.com's Pedro Moura and The Associated Press was used in this report.