The Washington Nationals recalled Wander Suero and optioned Austin Voth to Class AAA Syracuse on Monday, swapping a starter who was called up a day earlier as bullpen insurance for their top relief prospect.

Suero, 26, has been a dominant reliever in the Nationals’ farm system, but he wasn’t placed on the 40-man roster until November. He was one of the few effective relievers in Washington’s high minors not to get a chance at the big league level last season, when the Nationals’ bullpen was baseball’s worst until a July overhaul. The bullpen has more stability in the back end this year, but middle relief has been a glaring soft spot. Suero and his wipeout stuff figure to bolster that area.

Not getting called up last year “motivated me because, thanks to the year I had, I knew I was close,” Suero said in Spanish. “I knew I could achieve it, I knew I could play here. and that motivated me to work hard in the offseason to get here.”

The Nationals likely would have called up Suero earlier in the season, but the right-hander only recently returned from an oblique injury he suffered in a Grapefruit League game March 9. He said he was shut down for three weeks before he began throwing at the Nationals’ facility in West Palm Beach, Fla.

He made his season debut with Syracuse on April 21, allowing three runs on five hits in one inning. He rebounded to toss three scoreless innings over his next three appearances and didn’t issue a walk in any of the four outings. Last season, he pitched to a 1.79 ERA between Class AA Harrisburg and Syracuse. He attributed the success to developing his cutter, a pitch he said he learned to command on both sides of the plate. He carried over the success to the spring training, where he logged four scoreless innings with seven strikeouts and a walk before sustaining the oblique injury.

“I liked his ability to get both lefty hitters and righty hitters out,” Nationals Manager Dave Martinez said. “He’s got a really good cutter. And he throws strikes. That’s what you need out of the bullpen.”

Voth returns to Syracuse after he joined the Nationals for the first time Sunday morning. The 25-year-old right-hander was added as insurance in case the Nationals needed length after Washington used its entire bullpen Saturday. But Voth didn’t pitch and heads back to the International League without a big league appearance.

“We want Voth to continue pitching, starting and get him back on every five days,” Martinez said. “Suero gives us a little length. He can pitch multiple innings. I like what I saw out of him in spring training until he got hurt. So he’s a good fit.”

Suero last pitched on Saturday, tossing just 10 pitches in one inning, so he should be available Monday, as Washington opens a four-game series against the first-place Pittsburgh Pirates at Nationals Park.

PIRATES (17-11)
Adam Frazier 2B
Gregory Polanco RF
Sean Rodriguez CF
Josh Bell 1B
Corey Dickerson LF
Francisco Cervelli C
Colin Moran 3B
Jordy Mercer SS
Jameson Taillon RHP

NATIONALS (12-16)
Trea Turner SS
Ryan Zimmerman 1B
Bryce Harper RF
Howie Kendrick 2B
Matt Adams LF
Michael A. Taylor CF
Matt Wieters C
Wilmer Difo 3B
Tanner Roark RHP