Willie Warren, Oklahoma's leading scorer, was not in uniform for the Sooners' game against No. 7 Kansas State on Saturday night.
Warren, who had missed three of the previous seven games due to illness and injury, was on the bench in a polo shirt and jeans. Warren missed two games late last month with a sprained right ankle and then was held out of the game against Oklahoma State last weekend with what coach Jeff Capel called mononucleosis.
He returned to play four days later in a loss at Colorado.
Warren is averaging 16.3 points to rank ninth in the Big 12.