Mitch Mustain, 22, was taken into custody on Tuesday night by narcotics officers in the San Fernando Valley, an LAPD official said.
Mustain was booked on $30,000 bail. No other details of the arrest have been released.
Mustain became a backup quarterback for the Trojans after transferring to USC from Arkansas in 2007. He started in last season's game against Notre Dame when Matt Barkley was injured.
Mustain is currently preparing for the NFL draft.
The Associated Press contributed to this story.