Mayfield becomes the third opening - day starter at QB for OU in the last four seasons .
Texas Tech transfer Baker Mayfield won the starting quarterback job for the Sooners , beating out two - year starter Trevor Knight .
Mayfield becomes the third opening - day starter at QB for Sooners in the last four seasons .
Texas Tech transfer Baker Mayfield won the starting quarterback job for the Sooners , beating out two - year starter Trevor Knight .