Butler guard Rotnei Clarke is unsure when he can return to game action, but the school said Sunday he has a "significant neck sprain."
Clarke is no longer wearing the cervical neck collar required when he was injured Saturday at Dayton.
Clarke took a hard foul from Dayton's Matt Derenbecker and left on a stretcher with 8:13 left in the first half of the game won by the Bulldogs.
Though he was moving his arms, head and legs, paramedics stabilized Clarke on a backboard and placed him in a neck brace before he was taken to a local hospital for X-rays.
The initial diagnosis was a sprained neck, Butler head athletic trainer Ryan Galloy said. A CT scan was negative, and Galloy said Clarke had no fractures or spinal cord damage. Clarke's parents were at the hospital with him, and coach Brad Stevens left immediately after the game to join him.
Clarke, a 3-point specialist who transferred from Arkansas, entered play Saturday with a 3-point field goal percentage of .443.