Oregon already had injury concerns about Heisman Trophy candidate LaMichael James. The status of quarterback Darron Thomas is also not certain now.
It's unclear whether both stars will play Saturday as the ninth-ranked Ducks try to extend their win streak to six and hand injury-plagued Colorado a fifth straight loss.
James dislocated his shoulder during a 43-15 win over California on Oct. 6 and sat out last Saturday's 41-27 victory over then-No. 18 Arizona State.
Oregon (5-1, 3-0 Pac-12) finished its latest win without Thomas, who injured his left knee and was replaced by Bryan Bennett with the Ducks leading 21-17.
Bennett finished 2 of 5 for 22 yards as Oregon mainly ran the ball with Kenjon Barner, James' usual backup.
"No one really knew what Brian can do and he came in the game when it was close, and it was difficult and he showed what he can do," James said. "And I'm really proud of him."
Thomas insisted he was fine after the game, but ...