The team said he was taken to nearby Summit Medical Center for a CT scan.
Twins starter Anthony Swarzak hit Cunningham square in the helmet and knocked it off his head in the fourth inning Monday night, and the ball sailed high in the air. Cunningham dropped to one knee and athletic trainer Steve Sayles and manager Bob Geren rushed out.
Cunningham stayed in the game and slowly went to first after several minutes. Jack Hannahan cleared the bases with his double two pitches later.
But Gregorio Petit replaced Cunningham in the top of the fifth.