Coach Art Briles says Petty should be able to go after missing Baylor's last game with two cracked small bones in his back.
Petty was hurt on the first series of the season opener, and didn't dress out for Saturday night's 70-6 victory over FCS team Northwestern State.
Briles said Tuesday night that Petty would play after watching him for two days in practice this week.
Petty, the reigning Big 12 offensive player of the year, played only the first half in the opener against SMU. He completed 13 of 23 passes for 161 yards with two touchdowns and ran for another score.