Jake Locker missed the end of the Tennessee Titans' 38-13 win over the New York Jets after sustaining a hip injury.
The quarterback took a hit from Muhammad Wilkerson in the third quarter and was stretchered off the field into a waiting ambulance.
Head coach Mike Munchak told reporters: "He was in pain, and we don't know much more than that. He went to the hospital. They're checking on him now, so we'll get more information later. That's all we really have."
Offensive coordinator Dowell Loggains added: "This is the worst I've felt after a victory like this in a long time. I don't know what's going to happen, but I know he was hurt. If he misses one play in the game, then he was in pain."
Locker has completed 721 passing yards and six touchdown passes so far this season.