Braves general manager Frank Wren said Saturday left-hander Eric O'Flaherty has a torn ulnar collateral ligament in his left elbow.
The loss of O'Flaherty, who faces possible season-ending surgery, leaves the Braves in a sudden bullpen crisis.
On Thursday, left-hander Jonny Venters had season-ending surgery to reconstruct the ulnar collateral ligament in his left elbow. It is his second Tommy John surgery.
Also, right-hander Jordan Walden was placed on the 15-day DL with right shoulder inflammation on Friday.
O'Flaherty and Venters have been the team's top setup relievers in recent years. Walden had taken a set-up role this season. Now Wren and manager Fredi Gonzalez will have to scramble to find different ways to set up closer Craig Kimbrel.
"It's hard to lose two guys like we've lost," Wren said. "And we'll wait and see exactly how long Eric is going to be out, but it's not going to be a week or two, we know that."
It's a crucial test for the NL East-leading Braves, who entered Saturday one-half game ahead of Washington. The loss of O'Flaherty leaves Luis Avilan as the only left-hander in the bullpen. Anthony Vavaro and Cory Gearrin may assume bigger roles.
Wren said the Braves must answer the challenge.
"We have to. We don't have a choice," Wren said. "We've seen teams lose their closer and lose their set-up guys in the past and be able to regroup and make it work and we're going to have to do that."
Wren said O'Flaherty will see Dr. James Andrews for a consultation. Wren said a MRI on Saturday revealed the tear.
O'Flaherty was placed on the 15-day disabled list earlier Saturday with what was called a left elbow strain.
Right-hander Cory Rasmus was called up from Triple-A Gwinnett for Saturday night's game against the Dodgers. Rasmus, 25, is the younger brother of Toronto outfielder Colby Rasmus.
O'Flaherty, in his fifth season with the Braves, is 3-0 with a 2.50 ERA in 19 games. He had a 1.95 ERA through 276 appearances with Atlanta from 2009-12.
Like Venters, O'Flaherty assumed heavy workloads. He appeared in 78 games in 2009, 78 in 2011 and 64 in 2012.
"You look at every bullpen of winning teams, there are heavy workloads," Wren said. "That just goes with the territory."
Wren said Walden, placed on the DL retroactive to May 12, could return within a week. Right-hander Luis Ayala, placed on the 15-day DL with anxiety disorder on April 30, could return within two weeks.
The Braves could create more bullpen depth when right-hander Brandon Beachy makes his return from last season's elbow-ligament replacement surgery. Beachy is expected to make his second injury rehab appearance with Triple-A Gwinnett on Sunday and could make his return by the middle of June.
"That's going to create another move we're going to have to make to move someone from our rotation to the bullpen," Wren said. "As we get healthy and get some of our pitchers back, there will be other options for us. Still, we've got to figure out exactly how we move forward."