Oakland A's starter Frankie Montas has been suspended 80 games for performance-enhancing drug use, Major League Baseball announced on Friday, saying the right-hander tested positive for Ostarine.

His suspension begins immediately.

Losing Montas, 26, will be a blow to the A's, who are in third place in the AL West. In 15 starts, he is 9-2 with a 2.70 ERA and 97 strikeouts.