Oklahoma defensive end R Mason Thomas is unlikely to play against Alabama on Saturday because of a quad injury.

A final decision on Thomas' availability isn't expected until game time, sources told ESPN's Pete Thamel, but he is listed as doubtful on the SEC availability report.

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 is also doubtful to play against the Crimson Tide. He is set to miss a third straight game with a shoulder injury suffered Oct. 18 against South Carolina .

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