KANSAS CITY, Mo. — It has largely been forgotten and Chasen Shreve played more than a bit part in people forgetting so quickly.

What was it?

For the first five months of 2015, the lefthander was arguably as valuable a bullpen piece for the Yankees as Dellin Betances and Andrew Miller.

The numbers back up the claim.

Shreve, in compiling a 3.09 ERA in 59 outings, went 15 consecutive appearances without allowing a run — from May 24-July 1 — and even had a 1.86 ERA as late in the season as Sept. 5.

Joe Girardi trusted him against lefties and righties and was rewarded as Shreve, from May 6-Sept. 5 posted a 1.66 ERA, striking out 51 in 43 1/3 innings.

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Things derailed in a hurry, however, as Shreve allowed nine earned runs in his final nine appearances, putting up a 16.20 ERA in that stretch.

Though the 26-year-old seemed to put that behind him this spring — not allowing a hit or a walk during the Grapefruit League campaign — inconsistency plagued the reliever almost immediately after the regular season began, and he brought a 5.20 ERA, over three stints with the big-league club, into Wednesday night’s game. He has allowed seven homers in 30 appearances.

But Tuesday night might have been a breakthrough. Shreve and the Yankees certainly hope so.

Called on with the bases loaded and one out and the Yankees leading 5-4 to face the dangerous Kendrys Morales, the Royals leader in RBIs with 61, Shreve struck out the switch-hitter on three pitches. The final one was a splitter, set up by a pair of well-placed fastballs. Salvador Perez flied to center to end the game, which gave Shreve his first career save.

“I think I went away from what I do really well, which is locate my fastball,” Shreve said before Wednesday’s game. “And I think that’s why my splitter wasn’t getting the swings and misses it did last year. Going inside with my fastball is my biggest strength, I think. In Triple-A, I did it a lot . . . going in is key for me, and I think I had gone away from it.”

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It is, of course, a stretch to make grand pronouncements after one outing, one comprising all of five pitches. Still, with what Shreve was for five months last season and the Yankees on-going search for solid middle-relief, Tuesday night at least provides some hope.

“You hope it gets him on a roll,” Joe Girardi said. “I don’t think you jump to conclusions [based on one appearance] but you saw the swings and misses on the split, and I think that’s really important for him.”

Shreve, who spent time on the DL earlier in the season with a sprained AC joint in his left shoulder, posted a 1.62 ERA in 13 appearances with Scranton.

He had quite a day Tuesday, which started with him catching a flight in Buffalo in the morning, connecting through Detroit and arriving at Kauffman Stadium just before 3 p.m. About eight hours later, he found himself in the game’s biggest moment, the kind of scenarios last season he mostly excelled in.

“I look at the glove and try to focus on that and not the situation,” Shreve said.

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Situations, he said after the game and again Wednesday, he wants to be put in again.

“I want to be that guy that they have confidence in throwing in those situations,” Shreve said. “I don’t think the first five months of last year were a fluke. I think that’s who I am, and I think I can get back to that. It just takes time.”