Kwame Evans sparked the Ducks to a 50-36 lead before he fell to the floor in the second half, clutching his left knee.
The 6-10 former McDonald's All-American from Baltimore, Maryland had to be helped to the locker room. As he walked off he wasn't putting any weight on the leg.
Evans hasn't missed a game in two years. On Monday night against Hawaii he was a bright spot in a ragged game, shaking the Ducks loose with 3-6 shooting that included a powerful dunk and a sweet three, two blocks and three assists, just three of Oregon's disastrous 21 turnovers.