WASHINGTON — The Braves optioned left-handed reliever Ryan Buchter to Triple-A Gwinnett on Thursday to open a roster spot for reliever Pedro Beato, who was claimed off waivers Wednesday from the Reds.

The Braves began the season with an eight-man bullpen including three rookies with no previous major league experience — Buchter, sidearmer Gus Schlosser, and lefty Ian Thomas. Buchter was sent to Triple-A late in spring training, but recalled five days later after reliever Cory Gearrin injured his elbow in the last week of camp.

Schlosser and Thomas debuted in the opening series at Milwaukee; Buchter wasn’t used in that three-game series.

Beato, 27, was 4-2 with a 4.55 ERA in 81 career appearances in parts of three seasons with the Mets and Red Sox, with 56 strikeouts and 34 walks in 89 innings. He had a 3.60 ERA in 10 appearances with the Red Sox in 2013.

The bulk of his major league experience came with the 2011 Mets, when he posted a 4.30 ERA in 60 appearances and had 39 strikeouts in 67 innings.

Claimed off waivers by the Reds on Oct. 31, Beato pitched in nine spring training games and had a 3.00 ERA, allowing 11 hits, three runs and one walk with five strikeouts in nine innings.

Buchter didn’t pitch in the season-opening Milwaukee series, but other two rookie relievers, Gus Schlosser and lefty Ian Thomas, both debuted against the Brewers and drew praise from manager Fredi Gonzalez. The Braves have three left-handers with standout Luis Avilan and rookies Thomas and Buchter, making it likely that a lefty could be moved to open a spot for Beato.