Oklahoma State starting quarterback Wes Lunt left Saturday's game against Louisiana-Lafayette in the first quarter with a knee injury in the first quarter, according to USA Today.
Lunt, a true freshman, was injured on just the fourth offensive play of the game when he was tackled by a defender. He later went to the locker room on crutches with a wrap around the knee.
Lunt was replaced by J.W. Walsh, another freshman. Walsh threw a 52-yard touchdown to Kye Staley later in the quarter.
Lunt set a Big 12 freshman record in last week's loss at Arizona with 436 passing yards.