Oklahoma freshman quarterback left Saturday's Red River Showdown against Texas during the second quarter with an apparent biceps injury, according to Eric Bailey of the Tulsa World.
Rattler exited after getting sacked and losing a fumble while the Sooners were leading 10-3. He was replaced by sophomore Tanner Mordecai.
Prior to exiting, Rattler was 8-of-13 for 74 yards with one touchdown and one interception.
This article will be updated to provide more information on this story as it becomes available.
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