BOSTON -- After missing 17 games with right lat tightness, Brayan Bello returned from the injured list to make his first career start against the Nationals in Sunday’s 3-2 series-finale win at Fenway.

And with his return came a surprising corresponding roster move: Josh Winckowski was optioned to Triple-A Worcester to make room for Bello.

“This decision was based on the roster, what we feel we need right now is to win as many games as possible,” manager Alex Cora said pregame. “And obviously for him to be better.”

When it came time to make the decision, the luxury of having two very different lefty relievers in Brennan Bernardino and Cam Booser factored in heavily for Cora. Bernardino features a sinker, while Booser, who pitched a scoreless sixth on seven pitches (all strikes), uses a cutter, four-seam, sweeper mix.

Winckowski heads to Worcester with a 3.33 ERA across 12 appearances for the Red Sox, including a rotation-leading 1.69 ERA in three starts.

Despite being dealt a number of blows in the form of injured pitchers to start the season, Boston entered Sunday with an MLB-leading 2.75 ERA. Its rotation ranked first with a 2.42 ERA, while the bullpen carried an eighth-best 3.28 ERA.

On this date last year, Boston’s staff ranked 27th in the Majors with a 4.97 ERA. The bullpen (3.69) fared slightly better than the rotation (5.94), with the relievers ranking 11th compared to the starters’ 28th. The change in results can partially be credited to the arrival of pitching coach Andrew Bailey, who brought with him a new approach and mentality that Red Sox pitchers have quickly bought into.

Though last season’s pitching presented a number of problems for the Red Sox, Winckowski’s demotion represents a new “problem” for the club.

“We’re much more talented than last year,” Cora said. “There’s going to be tough decisions and there’s more tough decisions coming up.”

The Red Sox welcomed back Bello just days after Nick Pivetta rejoined the rotation following a stint on the IL with a right elbow flexor strain. Garrett Whitlock (left oblique strain) is set to make a rehab start on Wednesday, with a chance to return for the road series against the Rays that starts on May 20.

“Feels good to be back, feels good to help the team win and also it feels good that a lot of good things are happening for us right now,” Bello said through team interpreter Carlos Villoria. “A lot of guys are coming back, so it feels really nice.”

In his first start back, Bello worked around a first-pitch leadoff single to escape the first inning unscathed. His only blemish came in the fourth, after his second walk came back to bite him. With Nick Senzel on first, Eddie Rosario sent a middle-middle changeup into Boston’s bullpen for a two-run homer, despite center fielder Ceddanne Rafaela’s best efforts to reel it in on a dive over the right-center-field wall. Rafaela came up short on the play, but more importantly, he came up unharmed.

Bello has given up at least one home run in all but two of his seven starts (including one rehab outing with Double-A Portland) this season. His day was done after five innings, a marker that was set pregame as a precaution in his return. Though he said he didn’t feel “100 percent” in his first Major League start since April 19, Bello felt confident he’ll be back there in his next outing.

“He was OK. Command was off, the pitch to Rosario I think was a changeup that cut, put a good swing on it,” Cora said. “For his first one coming out of the IL? Good. Gave us five, two runs. So now he’ll be ready for the next one.”

With Bello back in Boston, Winckowski will join the rotation in Worcester and stretch out as a starter to give the Red Sox options down the line. Cora said Winckowski will focus on diversifying his repertoire, specifically developing a breaking ball for swing and miss.

“He’s very talented, he’s good,” Cora said. “He’ll start down there, we’ll put structure around him and at one point, he’s going to be back here. He’s going to contribute.”