Ian Krol (Matt Slocum / AP)

Left-handed reliever Ian Krol will be optioned to Class AAA Syracuse to make room for right-hander starter Ross Ohlendorf, who will return from the disabled list and start on Wednesday, according to Nationals Manager Davey Johnson. Krol is expected back when major league rosters expand on Sept. 1.

“He’s got a great future,” Johnson said. “He’s gonna be back in 10 days with the expanded rosters. I hate to miss him because he’s still learning up here. But he’s got a heck of a future.”

Krol, 22, was an unexpected call-up in early June as part of the Nationals bullpen overhaul. He was the ‘player to be named later’ in the winter trade for Michael Morse. He was at Class AA Harrisburg when the Nationals plucked him and thrust him into the majors. He threw well:  a 3.24 ERA and 20 strikeouts over 27 games. He began strong — 11 of his first 12 outings were scoreless — but tailed off since the mid-July.

Johnson expected to clear a roster spot for Ohlendorf with the release of Roger Bernadina, but the Monday trade for David DeJesus complicated matters. Ohlendorf will take rookie Taylor Jordan’s spot in the rotation after he was shut down on Friday in his first full season back from Tommy John surgery. Jordan’s lingering back issues hastened the shutdown. Ohlendorf has been out since Aug. 1 with right shoulder inflammation.

Krol is “going to Syracuse and he’s still learning,” Johnson said. “It’ll help him to get in a bunch of games and work on a few things. He’ll be back, but he’s got a heck of a future here.”

The Nationals’ bullpen will be left with only one left-handed reliever, Fernando Abad, in Krol’s absence. Abad has struggled against left-handers, who hit .320 against him. Right-handed long reliever Tanner Roark was effective against left-handers at Syracuse, holding them to a .198 average, but has only 10 major league innings under his belt. Tyler Clippard, who is dominant against hitters from both sides of the plate, is holding left-handers to a .158 average.

“I’m not real comfortable with it but it’s the best thing for right now,” Johnson said. “We’ve got some other things with some players that need to get some playing time and make some judgements on them.”