San Francisco Giants

A’s notes: Closer Doolittle goes on disabled list

The A’s will head into the final month of the season without their closer and, most likely, a valued platoon player.

Sunday afternoon, the A’s placed left-hander Sean Doolittle on the 15-day disabled list because of a strained right intercostal muscle. Doolittle, who has 20 saves and leads American League relievers in opponents’ on-base percentage, felt tightness in his right side during the ninth inning Saturday night and underwent an MRI before Sunday’s game.

The earliest Doolittle is eligible to return is Sept. 8, though he could be out longer depending on the severity of the strain. After first feeling discomfort on his second-to-last pitch Saturday, Doolittle said he did not believe the injury was too serious, though that was before the MRI.

In Doolittle’s absence, manager Bob Melvin said he will likely designate one reliever as a fill-in closer. “We have plenty of candidates that could do it,” he said.

Ryan Cook closed for the A’s in the past, and setup man Luke Gregerson and left-hander Eric O’Flaherty could warrant consideration.

The A’s recalled right-hander Dan Otero, who was optioned to the River Cats on Thursday, to replace Doolittle on the 25-man roster.

It was the second major transaction of the day for the A’s, who acquired catcher Geovany Soto from the Texas Rangers for cash considerations. The impetus for that move: Catcher John Jaso has experienced concussion symptoms since taking a foul tip off the mask two weeks ago and is likely headed to the seven-day concussion DL.

Jaso missed nearly the entire second half last season because of a concussion, but Sunday, he said his current symptoms are “not as bad as last year.” He said he experienced headaches and nausea for several days after the foul tip, and although those symptoms went away, he has continued to experience “fuzziness.”

Melvin said the concussion is “not something we can mess around with, especially with his history.”

Soto, 31, a career .248 hitter who has played in only 10 games this season amid injuries, is expected to join the A’s today in Houston as a backup catcher. Stephen Vogt is still dealing with foot pain and would be used behind the plate only in an emergency.

Third baseman Josh Donaldson, meanwhile, had an MRI on Sunday after tweaking his right knee in his final at-bat Saturday. Melvin, though, said Donaldson lobbied to be in the lineup Sunday, so the hope is the knee issue is not serious.