NEW YORK -- It spoke to the malleability of the Mets’ best-laid plans that, in the seventh inning of their 5-1 loss to the Yankees on Wednesday, Steven Matz was the reliever who trotted out of the bullpen. A charter member of what was supposed to be one of Major League Baseball’s most vaunted rotations, Matz shifted to relief work this week in what manager Mickey Callaway -- sort of -- called a temporary move.

Matz’s bullpen debut at Citi Field proved brief and effective. With two men on base and two outs in the seventh, he threw four pitches to lefty-swinging shortstop Didi Gregorius, inducing an inning-ending groundout on a 94.3-mph sinker. Half an inning later, Callaway removed Matz for a pinch-hitter to complete the lefty’s first scoreless outing since April.

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“It was definitely different,” Matz said. “You come in, the lights are on instead of the sun still [being] up, stuff like that. It’s definitely a different look. But at the end of the day, it’s still, you’ve got to go out there and pitch.”

While Callaway said Matz should return to the rotation after the All-Star break, he hesitated multiple times when asked if that’s certain, going as far as to indicate that Matz could stay in the bullpen longer. For now, consider such a prolonged residency unlikely, if only because the Mets have few options to fill in for him in the rotation. But also consider it telling. In the six starts prior to his bullpen shift, Matz was 1-3 with a 7.36 ERA.

“A little inconsistent, some blowup outings, but I think I’ve made some good strides this year,” said Matz, describing his season to date. “I’m happy with where I’m at.”

The Mets were already trailing by four runs when Matz made his relief debut, largely because starting pitcher Jason Vargas allowed hits to three of the first five batters he faced. The Mets also accomplished next to nothing against Yankees starter Domingo German, save for Jeff McNeil, who hit a leadoff homer in the bottom of the first inning.

It was an ideal spot for Matz to enter, with Callaway making sure to give the lifelong starter plenty of advance notice. The only difference in his routine? Matz did not long toss on the outfield grass, which he considered superfluous given the hot, sticky conditions -- 85 degrees at first pitch -- at Citi Field.

“I feel great,” Matz said afterward. “I feel like I can pitch every day like that, so we’ll just see what happens.”

Theoretically, this assignment is temporary. Wanting to give red-hot Zack Wheeler an extra start before the All-Star break, the Mets bumped Matz from their rotation earlier this week. When Matz talked things over with pitching strategist Jeremy Accardo, the two decided that Matz should volunteer to pitch out of the bullpen in the interim. It was an idea that “excited” him for two reasons: not only was it something different, but it also gave Matz a chance to bring some of his recent side work into big league games.

For a night, it all went swimmingly. For the future, time will tell. Although Callaway called this a short-term change, he brushed aside multiple chances to confirm Matz will return to the rotation after the break. Even Matz said that while he believes he’ll rejoin the starting five, he’s “not really sure.”

“I’m open to anything,” Matz said. “I really am. Honestly, whatever I can do to do the best I can to help the team win, that’s what I’m going to do. I like starting. That’s what I know. It’s what I’ve always done. I enjoy it. But I like pitching. So just whenever I can, I’ll go out there and pitch.”