Barkley made the announcement shortly after 1 p.m. at Heritage Hall at USC.
After a shaky start to the 2011 NCAA season, Barkley led the Trojans to a 10-2 finish. The Trojans finished the season ranked No. 5 in the nation.
Barkley is a strong prospect for professional football, standing 6 feet 2 inches and weighing 220 pounds. He was widely expected to be in the top 10 choices if he had decided to enter the National Football League draft.
