Trier was injured in Arizona's 103-101 double-overtime loss to the Trojans Saturday night. The school sent a release Sunday saying he will be out 4 to 6 weeks, but did not elaborate when he was injured.
Trier was the marquee player in coach Sean Miller's latest recruiting class and lived up to the hype early in the season, leading the Wildcats in scoring with 14.8 points per game.
Trier had 25 points against USC, his third time in four games with at least 20 points.
Arizona center Kaleb Tarczewski recently returned after missing eight games with a foot stress reaction.