The Nationals signed Shinnosuke Ogasawara over the winter believing the 27-year-old left-hander – the first Japanese free agent signing in club history – could become a viable major league starter, or at worst provide ready-to-go rotation depth at Triple-A Rochester.

The plan never was to use him as a reliever. Certainly not as a late-inning, high-leverage arm.

Funny how plans change. Because over the course of the last two weeks, Ogasawara has found himself pitching in a most unexpected role. And thriving in it.

Wednesday night provided the most dramatic example yet. Handed the ball for the top of the seventh with the Nats leading the Mets by one run, Ogasawara proceeded to retire Francisco Lindor, Juan Soto and Starling Marte in order, preserving a 5-4 lead that wound up holding through the game’s final out.

“He’s on a mission,” interim manager Miguel Cairo said. “I love the passion, the energy. That’s what you’re looking for when you put someone on the mound.”

Few could have foreseen this particular development.

After an unimpressive spring training, Ogasawara was sent to Triple-A to begin his professional career on this side of the Pacific as a full-time starter. The results were mixed: a 3.71 ERA and 1.324 WHIP in eight starts, with a lengthy stint on the injured list due to an oblique strain thrown into the mix as well.

The Nationals promoted Ogasawara to make his major league debut July 6 against the Red Sox, not so much because he had earned it but because he was the only viable choice at that point to replace the injured Trevor Williams. He proceeded to get roughed up for four runs and seven hits in only 2 2/3 innings, suffering the loss on what proved to be the day both Davey Martinez and Mike Rizzo were fired.

Another unimpressive start the next week in Milwaukee followed, and the Nats optioned Ogasawara back to Rochester. But following a spate of trades at the July 31 deadline, the club called him back up and put him in the bullpen, figuring he could provide some value as a long man.

Turns out he’s been far more valuable in shorter bursts. Ogasawara has made three relief appearances totaling two or more innings, and he’s been scored upon in each of them. He’s also made four appearances of no more than 1 1/3 innings, and he has yet to surrender a run in any of them.

“This is a new experience for me,” he said, via interpreter Kiyoshi Tada. “So I’m just trying to work on it and enjoy it as much as I can.”

Cairo hasn’t hesitated to see how Ogasawara fares against some of the best hitters in the major leagues. He has now faced Kyle Schwarber, Bryce Harper, Lindor and Soto in the last three days alone, and they’ve collectively gone 0-for-5 against him. Left-handed batters as a whole are 1-for-11 against him since he became a reliever.

All told, Ogasawara has allowed only three hits over his last 8 1/3 innings. And three times he has pitched in a high-leverage spot out of the bullpen, capped by Wednesday’s high-pressure assignment in the seventh inning of a 5-4 game.

“That situation, only one run, is different,” he said. “But I just tried to focus on the games and make sure I’m ready for the next inning.”