Looking to add another piece to their impressive bullpen depth, the A's agreed to terms Wednesday on a two-year deal with free-agent left-handed reliever Eric O'Flaherty. The deal is for $7 million over the two years, according to Ken Rosenthal of FoxSports.com.

To make room on the 40-man roster, Oakland designated outfielder Corey Brown for assignment.

O'Flaherty, 28, is coming back from Tommy John surgery that limited his 2013 campaign to 19 games with the Braves, but he's expected to be healthy by midseason. He was 13-7 with a 1.99 ERA over 295 appearances with Atlanta over the past five seasons after opening his career with three seasons in Seattle.

The 6-foot-2, 220-pound southpaw compiled a 1.45 ERA in 161 appearances over the past three years, which is the lowest mark among Major League relievers with 125 or more innings pitched. O'Flaherty held opponents to a .220 batting average over that span, including .156 against left-handed hitters.

O'Flaherty's 0.98 ERA in 2011 made him the first Major League pitcher to produce a sub-1.00 ERA while making at least 70 appearances.

The addition of O'Flaherty bolsters an A's bullpen in which Sean Doolittle is the only returning left-hander, though the club also acquired Fernando Abad in a trade with the Nationals in November. Oakland has already added right-handed closer Jim Johnson and setup man Luke Gregerson this offseason.

In his eight-year Major League career, O'Flaherty has limited left-handed hitters to a .200 batting average and a .531 OPS in 542 plate appearances, while right-handers have hit .270 with a .717 OPS in 796 plate appearances.

O'Flaherty was 3-0 with a 2.50 ERA and a 0.94 WHIP in 18 innings for the Braves last year before being shut down on May 18. He underwent Tommy John surgery three days later after tests revealed a tear in his left elbow's ulnar collateral ligament.

Brown, 28, was reacquired from the Nationals for cash on Dec. 19 after going 2-for-12 (.167) with a home run and one RBI in 14 games during a September callup with Washington. He spent most of the season with Triple-A Syracuse, where he hit .254 with 19 home runs and 56 RBIs in 107 games.

Brown was originally drafted by the A's as a compensation pick following the first round of the 2007 First-Year Player Draft and was sent to Washington as part of the Josh Willingham trade following the '10 season.