Brewer was injured early in the fourth quarter of Saturday's win against Kansas State and didn't return. Freshman Gerry Bohanon replaced him in the 31-12 Bears victory.
Speaking on Monday's Big 12 conference call, Rhule called Brewer's exit Saturday precautionary.
"He was hit hard, so they evaluated him," Rhule said. "It was precautionary, especially at that time in the game. He seemed to be fine. He didn't play the rest of the game, but he's cleared to go."
Brewer, a junior, has thrown for 11 touchdowns without an interception this season. No. 22 Baylor is off to a 5-0 start.