The Trojans opened at 20-1 after the conclusion of last season.
Ohio State, which defeated Oregon to win the inaugural College Football Playoff, is the favorite at 7-2.
Alabama is 7-1, TCU 10-1 and Auburn 12-1.
Florida State improved from 33-1 to 12-1 after Notre Dame quarterback Everett Golson confirmed Tuesday that he would transfer and play for the Seminoles.
Oregon is 22-1, UCLA 28-1 and Stanford 33-1.