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."
• 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.