The Athletics placed right-hander J.T. Ginn on the 15-day injured list Wednesday due to a blister on his right middle finger.
The move is retroactive to Saturday for Ginn, who leads the team’s starters in wins (eight), ERA (3.46) and strikeouts (100) while making 22 appearances (19 starts) this season.
Ginn, 27, allowed just one hit and struck out seven batters over 6 1/3 scoreless innings in a 15-1 romp over the Washington Nationals in his last trip to the mound.
He is 13-14 with a 4.20 ERA in 53 career games (41 starts) with the Athletics.
Also on Wednesday, the A’s recalled right-hander Mason Barnett from Triple-A Las Vegas.
Barnett, 25, is 1-0 with two saves and a 4.64 ERA in 13 relief appearances with the Athletics this season. He is 3-1 with a 4.34 ERA in 10 games (all starts) with the Aviators.
