WASHINGTON -- The Nationals do not have a left-hander in the Major League bullpen, but there is a familiar southpaw in their Minor League system.

Sean Doolittle was promoted to Triple-A Rochester from Double-A Harrisburg on Thursday. He completed his rehab assignment (left elbow) on June 6. Doolittle, 36, underwent a season-ending internal brace procedure last July, and he signed a Minor League deal with the Nationals in November.

“We’re keeping an eye on him,” Nationals manager Dave Martinez said Saturday. “It’s no secret we have no left-handed relief pitchers, so we’re definitely looking at all the guys that we’ve got and he’s one of them.”

Doolittle threw 3 1/3 innings with two runs allowed (5.40 ERA) in three appearances with the Senators. He has pitched in two games with the Red Wings, giving up three runs in two frames (13.50 ERA).

“I want to see him pitch back-to-back days, I want to see him throw 25 pitches in a game -- if he has to -- and get left-handers out. That’s the big thing, right?” Martinez said. “We still talk about him, we still watch him, he’s still involved in what we’re trying to do, which is to try to find a lefty that we can use up here.”

Double-A Harrisburg Senators
Third baseman Trey Lipscomb was promoted to Double-A on June 9. Days later, the Nationals’ No. 18 prospect homered in back-to-back games with the Senators on Tuesday and Wednesday.

High-A Wilmington Blue Rocks
Center fielder Jared McKenzie (No. 23) doubled in four consecutive games from June 11 through Thursday. In the first 14 games of June, McKenzie recorded 14 RBIs.

Single-A Fredericksburg
Starting right-hander Bryan Caceres has given up only four runs (one earned) in his past three outings. On Wednesday, he recorded five strikeouts in as many scoreless innings.