Sean Doolittle has landed on the disabled list.
Sean Doolittle has landed on the disabled list. (USATSI)

The Oakland Athletics announced Sunday that they have placed All-Star closer Sean Doolittle on the 15-day disabled list due to a strained right intercostal (ribcage) muscle. As a corresponding move, reliever Dan Otero has been recalled from Triple-A Sacramento.

Doolittle, 27, has closed down 20 of his 23 save chances this season with a 2.28 ERA, 0.71 WHIP and 80 strikeouts against only five walks in 55 1/3 innings. He hasn't allowed a run since the All-Star break, so obviously this is a big blow to the A's.

Otero is no slouch, though. The 29-year-old right-hander has a 2.28 ERA and 1.07 WHIP in 71 innings this season. He's been fortunate enough to vulture seven wins, too, as he sports a 7-1 record.

With Doolittle out, the A's could use Luke Gregerson, Ryan Cook, Eric O'Flaherty or even Otero in save situations.

In other A's news, Josh Donaldson is having a precautionary MRI on his balky knee.