Fullback Trey Millard tore knee ligaments in Oklahoma's 38-30 victory over Texas Tech on Saturday in Norman, Okla., and will miss the remainder of the season.
Sooners coach Bob Stoops said the players were crushed by the news of Millard's injury after knocking off the previously unbeaten Red Raiders. Millard is expected to have surgery in a few weeks.
Millard carried once for six yards and caught one pass for 14 yards against Texas Tech.
A senior, Millard has started since his freshman season. He had rushed for only 91 yards and added 64 yards receiving this season, but he played a key role in the offense with his run blocking and pass protection.
Junior Aaron Ripkowski likely will take Millard's place in the lineup for the rest of the season.