Oklahoma State junior quarterback JW Walsh left the first quarter of Saturday's game against Missouri State with an apparent ankle injury.
He returned to the sidelines on crutches with his right ankle wrapped, having reportedly suffered an ankle sprain.
Junior Daxx Garman replaced Walsh on the Cowboys' next series.
Walsh completed 113 of 190 passes for 1,333 yards and nine touchdowns over eight games last season. He passed for 203 yards and a touchdown and added two scores on the ground in last week's 37-31 loss to top-ranked Florida State.
- Chris Johnson