A's designate lefty O'Flaherty for assignment

OAKLAND -- The A's designated Eric O'Flaherty for assignment Saturday amid a consistent string of struggles for the veteran left-hander.

O'Flaherty allowed 14 earned runs in 21 1/3 innings over 25 appearances this season with the A's, who signed him to a two-year, $7 million deal as a free agent ahead of the 2014 season.

It was a risky signing for a reliever recovering from Tommy John surgery, and O'Flaherty didn't make his A's debut until July of last year, returning to the mound to post a 2.25 ERA in 21 games. He was expected to post similar numbers in a setup role this year, but he was sidelined for a month with a left shoulder strain and never really got back on track.

The A's used his roster spot for Saturday starter Aaron Brooks, who started in Saturday's 5-1 win after being acquired this week in a deal with the Royals for Ben Zobrist.

"It's not uncommon after Tommy John that it takes a while, some guys more than others," A's manager Bob Melvin said. "It's taken him a little longer."

O'Flaherty, 30, was a lights-out workhorse in the Braves' bullpen, posting a 1.99 ERA from 2009-13. At times he showed flashes of his old form in an A's uniform, but opponents hit .312 against him this year, including .420 by right-handers.

"I know he was frustrated with it, but that doesn't mean at some point in time it won't come around for him," Melvin said. "We had to make a move obviously, and it was tough to do because we were invested in him, but this is the decision we came up with."

Worth noting

• Left-hander Sean Doolittle (shoulder strain) threw his second bullpen in three days Saturday, totaling 31 pitches without any issues.

• Newly acquired southpaw Felix Doubront was set to join the A's on Saturday is expected to be activated Sunday, at which point the club will determine a role for him.