Oregon quarterback Dennis Dixon (10) is treated by trainers after injuring his knee. Tebow sustained a torn ACL in Oregon's loss to Arizona on Thursday, ending his season and Heisman Trophy aspirations.

Dennis Dixon will have surgery on the left knee that buckled early in second-ranked Oregon’s upset loss to Arizona, spoiling his chance to win the Heisman Trophy.

The quarterback tore his anterior cruciate ligament during Oregon’s Nov. 3 victory over Arizona State, according to coach Mike Bellotti, but he had rested it and felt as if he was ready to play Thursday night against the Wildcats.

Now Dixon will miss the rest of this season.

“He’s a little bit despondent, because he obviously wanted to continue to play,” Bellotti said.

The versatile Dixon was one of the front-runners for the Heisman after he put the Ducks in line for the national title. Oregon had started the season unranked, and was picked to finish sixth in the Pacific-10 Conference.

Drawing comparisons to Vince Young, Dixon completed 67.7 percent of his passes for 2,136 yards, 20 touchdowns and four interceptions. The senior from San Leandro, Calif., also ran for 583 yards and nine scores.