STANFORD, Calif. (AP) -Stanford left tackle Allen Smith will miss 4 to 6 weeks with a sprained right knee, a tough break for the sixth-year senior who had worked his way back after being sidelined the past two seasons with serious left knee injuries.

Smith sprained the medial collateral ligament in his knee when another player fell on him during Saturday night's 33-14 home victory against Arizona State. The win moved the Cardinal within one victory of becoming bowl eligible. Coach Jim Harbaugh hopes Smith will return this season.

Stanford (5-3, 4-2 Pac-10) also is without junior tailback Jeremy Stewart indefinitely. Harbaugh said Tuesday that Stewart injured his ankle Sept. 26 against Washington and hasn't practiced or played since.