In a deal first reported by FoxSports.com, the 38-year-old reliever agreed to a one-year, $7 million contract with the Braves with a vesting option for a second year. The vesting option is worth $6.5 million and will become guaranteed if Wagner finishes 50 games next season.
Boston, which offered arbitration to Wagner on Tuesday, will receive two draft picks — likely a first-rounder (20th overall) and a sandwich pick between the first and second rounds – as compensation.
Wagner was acquired by the Red Sox from the Mets last August and posted a 1.98 ERA in 13 appearances in a set-up role. The veteran left-hander has 385 career saves and will replace Rafael Soriano and Mike Gonzalez, the Braves' co-closers last season, in Atlanta's bullpen.
Calling himself a lifelong Braves fan who grew up watching the team on TBS, Wagner said it's always been his goal to pitch for Atlanta. The deal came together quickly after Braves GM Frank Wren, manager Bobby Cox and pitching coach Roger McDowell flew to Wagner's rural Virginia home to make their pitch in person.
"I grew up loving Dale Murphy. I remember Bob Horner hitting four home runs in a game," Wagner said. "They have such a great tradition of winning and competing and great guys. I wanted to be a part of that. I'm excited about the opportunity. They'll get the best I have to offer."
Soriano (27 saves) and Gonzalez (10 saves) shared the closing duties last season, but both became free agents and are expected to sign elsewhere. The Braves immediately targeted Wagner, considering him a better option than either of the incumbents.
Wagner had elbow ligament replacement surgery on Sept. 10, 2008, but said his arm feels better than it has in years.
"I never had any discomfort. I never felt like I had to back off," he said. "If I had known it was going to work out this well, I would have had Tommy John (surgery) five years ago."
The Braves' signing of Wagner and re-signing of Tim Hudson show that they are serious about sending Cox out a winner in his final season as skipper.
Information from The Associated Press was used in this report.