The back of the bullpen has been one of the Braves’ great strengths in recent years; all of a sudden it’s a point of concern.

The Braves learned Saturday that top setup man Eric O’Flaherty has a tear in his ulnar collateral ligament, just two days after another top left-handed reliever, Jonny Venters, underwent season-ending surgery for the same problem.

Braves general manager Frank Wren said an MRI taken Saturday revealed a tear in O’Flaherty’s left elbow, and he was headed to see noted orthopedic surgeon Dr. James Andrews.

Tears of this nature almost always mean ligament-transplant surgery and at least a 12-month recovery, though Wren said the Braves won’t know for sure until O’Flaherty sees Andrews.

“Until we take the next step, we’ll wait and see,” Wren said. “Obviously you’re hoping that it’s just a sprain and a short DL stint, and you can come back fairly quickly, but it doesn’t look like that’s going to be the case.”

O’Flaherty complained of soreness after pitching an inning Friday night against the Dodgers. He threw 13 pitches in the eighth, giving up a solo home run to Scott Van Slyke in an 8-5 win. O’Flaherty went 52 appearances, from June 8 to April 29, without allowing a home run, while putting up a 0.76 ERA. He has allowed two home runs in his past seven appearances.

The Braves placed O’Flaherty on the disabled list Saturday and recalled Cory Rasmus from Triple-A Gwinnett. O’Flaherty was examined Saturday by Braves team orthopedist Dr. Gary Lourie.

“He’s had some tenderness, but not anything abnormal,” Wren said. “But last night after he threw — actually after we all left — I got a call when I was halfway home, that he came back in after starting to do his postgame workout, that he had some abnormal soreness.”

The Braves entered the season with O’Flaherty, Venters and Jordan Walden projected as their top three set-up men behind closer Craig Kimbrel. All three have had health-related problems revealed in the past three days.

The Braves put Walden on the disabled list Friday with shoulder inflammation, though Wren said he should be able to return when he’s eligible May 27. Wren said Luis Ayala, who was on the disabled list with an anxiety disorder, could return in the next week or two. The Braves could also move a starter to the bullpen when Brandon Beachy returns from elbow surgery in June.

In the meantime the Braves will use left-hander Luis Avilan in the eighth inning spot, as well as Cory Gearrin.

“We’ve seen teams lose their closer, we’ve seen teams lose their setup guys in the past, and be able to regroup and make it work,” Wren said. “And we’re going to have to do that.”

Wren said that this early in the season there aren’t many options on the trade market. The Braves will continue to evaluate internal options, though they are not inclined to turn to Alex Wood, a 6-foot-4 left-hander from the University of Georgia who made such a good impression during spring training.

Wood is 2-2 with 0.82 ERA in eight starts for Double-A Mississippi.

“I don’t think we need to disrupt the development of players at this point,” Wren said. “We’ll let them continue to develop and grow. He’s doing really well, but we’re not to the point where we think that would be advantageous to him or us.”

O’Flaherty is tied for 21st in the majors with 217 appearances over the past three years. Entering the season, Venters trailed only Sean Marshall for the major league lead in appearances since 2010, with 230 to Marshall’s 231. When asked if a heavy workload was starting to catch up to the Braves’ bullpen, Wren said it’s a necessary evil for winning teams.

“You look at every bullpen of winning teams, there are heavy workloads,” Wren said. “That goes with the territory. When you have a team that’s winning a lot of games, pitchers pitch a lot.”

The Braves already are playing short-handed, with six relievers in the bullpen so they can keep three catchers, including Evan Gattis, on the roster. They’re still taking that day by day and will continue to at least through the rest of this six-game homestand.

“It’s easy for us because we have a Triple-A team 30 minutes away,” Wren said. “You don’t need that extra guy. Historically, teams went with 11 pitchers — that was the norm.”

Rasmus, a right-hander and younger brother of Toronto outfielder Colby Rasmus, went 7-for-7 in save opportunities with a 0.93 ERA in 19 appearances for Gwinnett.

The Braves also recently signed left-hander Joe Beimel to a minor league deal. Beimel, 35, who is coming off elbow-reconstruction surgery of his own (May 1, 2012), has a 4.21 career ERA in 567 games over 11 seasons with the Twins, Rays, Dodgers, Nationals, Rockies and Pirates.