USC running back Ronald Jones is wearing No. 4 in honor of former Trojans running back Joe McKnight, who was killed in Louisiana last month.
McKnight was reportedly in a conflict at a highway intersection and attempting to apologize to another man, who then shot him more than once.
Ronald Gasser was initially released without charges but later arrested and jailed on a charge of manslaughter.
McKnight was a star for USC from from 2007 to 2009 and went on to play three seasons with the New York Jets and one season with the Kansas City Chiefs. He last played for the Saskatchewan Roughriders of the Canadian Football League.