Montas tallied 97 strikeouts with a 2.70 ERA before Friday's suspension.
A's starting pitcher Frankie Montas was suspended 80 games after testing positive for a banned substance, according to ESPN's Jeff Passan.
The 26-year-old righty posted a 2.70 ERA in 15 starts prior to Friday's suspension. He won nine games and struck out 97 batters in 90 innings, posting a career-best 1.12 WHIP.
Montas has a career 3.92 ERA in 202 innings.
Oakland sits third in the American League West at 40–36 with five wins in its last six games. Last season, the A's reached the postseason for the first time in 2014 before losing to the Yankees in the American League Wild Card.