USC offensive lineman Khaliel Rodgers suffered a knee sprain and could be sidelined for two weeks.
Rodgers was injured Monday night during a scrimmage at the Coliseum.
Rodgers, a redshirt freshman, has been playing with the first-team offense at right guard.
He is the third USC player to be sidelined because of a knee injury.
Defensive lineman Kenny Bigelow suffered a season-ending injury during the summer and linebacker Jabari Ruffin suffered a season-ending injury early in training camp.
Freshman Damien Mama and senior Aundrey Walker are expected to work in Rodgers' place as the Trojans continue preparations for their Aug. 30 opener against Fresno State.
USC did not practice Tuesday. The Trojans resume workouts Wednesday.