Foster was hit in the sixth inning by a foul ball from Kevin Smith and collapsed to the ground before being helped to his feet by A's assistant athletic trainer Brian Schulman.
Foster remained in the game, but in the top of the seventh, Oakland reliever Zach Jackson threw a low pitch that bounced up and hit Foster again. Second-base umpire Scott Barry replaced Foster behind the plate in the 4-1 Angels win.
Umpire exits Angels-A's game after getting hit twice
Marty Foster, the home plate umpire for Angels vs. A's, leaves the game after getting hit in the mask in both the sixth and seventh innings