A’s closer Doolittle heads to 15-day DL

O.CO COLISEUM —  After a second strike to Angels shortstop Erick Aybar Saturday night, Oakland closer Sean Doolittle felt some pain in his side.

That pain has been officially diagnosed as a strained right intercostal, and baseball’s best closer is headed for a stint on the 15-day disabled list.

Doolittle said Sunday:

“Last night, I was in a little bit of pain after the game. But the trainers, we were talking about it, there was so many different things that it could have been, that we didn’t want to speculate one way or another until we got some pictures taken of it today.”

Doolittle called his injury timetable day-to-day, and talked about when he might return:

“Right now, they haven’t been real specific, which is good. I’ve dealt with a lot of injuries in the past, and timetables can be frustrating. When you’re setting benchmark goals for yourself along the way, as soon as you miss one, even if it’s a bad day, than can be real frustrating.”

To take his spot on the roster, the A’s recalled right-handed pitcher Dan Otero from Triple-A Sacramento.

Doolittle is 1-3 with 20 saves and a 2.28 ERA in 54 relief appearances. In just over 55 innings of relief this season, Doolittle issued just five walks and has 80 strikeouts for a strikeout-to-walk ratio of 16.00.

Doolittle leads American League relievers in opponents on-base percentage (.190), ranks fifth in strikeouts, sixth in opponents slugging percentage (.256) and eighth in saves and opponents batting average (.171). He leads Major League relievers in strikeout-to-walk ratio and is averaging the fewest walks per nine innings (0.81).

Otero, who was on Oakland’s opening day roster, has a season ERA of 2.28 in 56 relief appearances. He was optioned to AAA on Thursday to make room on the 25-man roster for outfielder Craig Gentry.

Doolittle said he’s wholly confident in the healthy bullpen arms:

“That’s been something we’ve been talking about all year, the depth of this bullpen. There’s a number of guys that have experience in late game situations. Whether its a setup role, or coming in to close on a given night if somebody’s been unavailable. You look at the versatility and the way we can match up, and the experience, I think that they’re more than capable of figuring out a way to continue to get the job done.”

Otero did not throw a single pitch with Sacramento, and will arrive fresh and ready to go.

With the A’s, Otero has allowed a .250 opponents batting average and has issued just nine walks, an average of 1.14 per nine innings. He leads AL relievers in wins, ranks second in innings pitched (71.0) and is third in fewest walks per nine innings.

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