Athletics P Sean Manaea Placed on DL with Shoulder Injury; Will Get MRI

The Oakland Athletics placed starting pitcher Sean Manaea on the 10-day disabled list with a left shoulder impingement, the team announced Sunday.

The San Francisco Chronicle's Susan Slusser reported Manaea is set to undergo an MRI in the Bay Area to determine the severity of the injury.

Manaea is 12-9 with a 3.59 ERA in 27 starts this season.

Slusser had previously noted his velocity was trending downward for some time, which can be an indication of shoulder issues.

According to Brooks Baseball, he's averaging 90.6 mph on his fastball in August, which is a career low for a single month. During the 2016 season, Manaea was regularly hitting 93 and 94 mph with his fastball.

His injury couldn't come at a worse time as the A's try to catch the Houston Astros in the American League West—or at the very least secure a wild-card berth. Oakland is 1.5 games back of the Astros and five games up on the Seattle Mariners for the final wild-card spot.

Before losing Manaea for at least the next week and change, pitching was the Athletics' biggest question mark. According to FanGraphs, Oakland starters are 17th in FIP (4.27). That number isn't terrible but less than ideal for a team with postseason ambitions.

So far, the patchwork Athletics rotation has defied expectations.

Maintaining that over the stretch run won't be easy, especially if Manaea's shoulder injury keeps him out for an extended period of time.