For the second straight day, the A's pitching staff took a big hit.

On Friday, ace Frankie Montas was suspended for 80 games. A day later, the A's lost All-Star closer Blake Treinen to the injured list.

"Blake has a mild shoulder issue right now," manager Bob Melvin told the media after the A's 4-2 win over the Rays at the Coliseum. "It's muscular in nature and we're going to put him on the IL."

Coming off a historic 2018 season, Treinen hasn't been as dominant this season. In 35 1/3 inning, he's posted a 4.08 ERA and has converted 16 of 18 save opportunities.