Dennis Dixon will have surgery on the left knee that buckled early in second-ranked Oregon's upset loss to Arizona, costing the Ducks a shot at the national championship and likely 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 like he was ready to play Thursday night against the Wildcats.

Now Dixon will miss the rest of this season.

The versatile Dixon was one of the front-runners for the Heisman award 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.

Dixon completed 67.7 percent of his passes for 2,136 yards, 20 touchdowns and four interceptions. He also ran for 583 yards and nine scores.

Thursday night's 34-24 loss to the unranked Wildcats knocked the Ducks (8-2, 5-2) out of the national title picture. Oregon was ranked behind LSU and ahead of Oklahoma and undefeated Kansas.

Dixon's left knee crumbled as he tried to plant on an option carry with about 5 minutes to go in the first quarter against Arizona (5-6, 4-4).