The Oakland Athletics have optioned right-hander Tyson Ross to Triple-A Sacramento.
The team made the move on Thursday's off-day. Oakland is expected to activate outfielder Yoenis Cespedes on Friday in Kansas City to take Ross' place on the 25-man roster.
Ross was 2-6 with a 6.51 ERA in nine starts with the A's. He was 1-0 with a 2.13 ERA in his first two starts but went 1-6 with an 8.13 ERA over his past seven.
Ross got charged with three additional earned runs on Thursday because of a scoring change from his start last Friday against the New York Yankees. A ball originally ruled a two-base error on Coco Crisp was changed to a double for Robinson Cano by MLB executive vice president Joe Torre.