Rockwell was a backup quarterback for Michigan at the start of the 1923 season but got the starting quarterback job after Irwin Uteritz broke his ankle in a game against the Quantico Marines. When Rockwell came into the game against the Marines, Michigan lined up for a field goal with Rockwell holding the ball. As the Marines came through to block the kick, Rockwell jumped to his feet and ran the ball 26 yards for a touchdown. The touchdown run was Rockwell's first play for Michigan's varsity team. The following week, Rockwell played back to receive a kick against Wisconsin. The ball bounced off his chest at the 32-yard line, and Rockwell picked up the loose ball. Rockwell was hit and appeared to be knocked down, but the whistle was not blown and Rockwell continued running 68 yards through