Mahomes was injured on a quarterback sneak on fourth down with just over nine minutes remaining in the first half. As medical staff attended to him on the field, it appeared Mahomes’ knee was straightened and popped back into place.
A cart came onto the field, apparently to take Mahomes for treatment. He was instead helped off the field by a couple of trainers. Players from both teams came by to offer encouragement.
Mahomes, 24, soon left for the locker room, walking under his own power but with a limp. He was in the X-ray room for only two minutes before the Chiefs ruled him out, according to the Fox broadcast.
Veteran Matt Moore, who joined the Chiefs late in the preseason, replaced Mahomes.