Oklahoma defensive end R Mason Thomas will not play against Alabama on Saturday because of a quad injury.
Thomas suffered the injury while returning a fumble 71 yards for a touchdown during the Sooners' Nov. 1 win over Tennessee.
Oklahoma's best defensive player, Thomas has a team-leading 6.5 sacks this season along with two forced fumbles and the scoop-and-score fumble recovery.
Starting cornerback Gentry Williams also was ruled out against the Crimson Tide. He will miss a third straight game with a shoulder injury suffered Oct. 18 against South Carolina.