Former Southern California backup quarterback Mitch Mustain was arrested on suspicion of selling prescription drugs in the San Fernando Valley, police said Wednesday.

Mustain, 22, was arrested by West Valley narcotics officers shortly after 8 p.m. Tuesday and booked on $30,000 bail, Officer Bruce Borihanh said.

Details of the arrest were not immediately released.

The Los Angeles Times reported that Mustain was released on bail but Borihanh said he could not confirm that and a Los Angeles County Sheriff's Department jail website still listed him as being in custody late Wednesday morning.

Mustain completed his senior year for the Trojans in 2010 and could not be reached for comment through the university's athletic department. The school had no contacts for him and it was unclear whether he had an agent.

Mustain currently is preparing for the NFL draft.

He became a backup quarterback for the Trojans after transferring to USC from Arkansas in 2007.

He started in last November's loss against Notre Dame when Matt Barkley was injured and passed for 177 yards. It was his first start since his freshman season at Arkansas, when he went 8-0.