Receiver Ty Montgomery, Stanford's top returning playmaker, is questionable for the season opener against UC Davis and could miss the Week 2 showdown against USC as he recovers from an arm injury, Cardinal coach David Shaw said Thursday.

Montgomery, who missed spring practice after surgeries on his knee and arm, is ahead of schedule and able to run full speed. But he is not ready for contact drills and will be limited for at least the first portion of training camp.

"Hopefully, by the end of training camp, he'll be able to do more contact stuff," Shaw said. "He might not play the first game, and it will be close for USC."

Shaw declined to describe the exact nature of the arm injury, but it believed to involve Montgomery's elbow.