Happ was hit by a batted ball Tuesday and taken from the field on a stretcher. He motioned to the crowd as he was leaving the field, however.
The Blue Jays said Happ suffered a head contusion and laceration to his left ear. He was undergoing additional testing but was released from the hospital Wednesday.
Happ was hit in the head by a line drive hit by Tampa Bay's Desmond Jennings in the second inning of the game. The ball bounded down the right-field line, incidentally for a two-run triple, and Happ collapsed to the ground.
Medical personnel quickly reached Happ and took him off the field.
Toronto won the game 6-4.