OAKLAND -- A's outfielder Khris Davis exited after the sixth inning Saturday against the Yankees with tightness in his right forearm.
The injury came on a throw from left field after a sacrifice fly in the fourth inning off the bat of Aaron Hicks. Starlin Castro scored without a play at the plate.
Davis declined to be interviewed by reporters after the game.
He is "day to day," manager Bob Melvin said.
The A's are already short-handed with 12 players on the disabled list, the club's most at one time since 1979.
Davis has been their best power hitter, with his 12 home runs ranking second in the American League heading into Saturday. He's had nine home runs in his last 16 games.