Coach Lane Kiffin  announced freshman Max Wittek will make his first career start in place of Barkley.
In three appearances this season, Wittek has completed 8-of-9 passes for 95 yards and a touchdown with no interceptions. He has been sacked once. His debut will not be an easy one, as he faces the top-ranked Irish at the Los Angeles Coliseum.
Barkley was injured in the final minutes of the Trojans’ 38-28 loss to UCLA on Saturday when he was sacked by linebacker Anthony Barr. Barkley was down on the field for a few minutes and was replaced by Wittek on USC’s final series.
Following the game, Barkley left the stadium with his right arm covered by a sweater. His shoulder appeared to be supported by a sling, but he would not comment on the injury, citing the program’s policy.
“I feel bad for him and his family,” Kiffin said. “This is obviously not how you want it to be.”