SEATTLE — Just as the Yankees were feeling good about their overall health, Jake Cousins walked off the mound with a trainer in the sixth inning of Thursday’s 3-2 loss to the Mariners. 

Cousins left the game with right pec tightness after only throwing six pitches — the last one a slider that struck out Julio Rodriguez, at which point Aaron Boone and a trainer popped out of the dugout to visit Cousins on the mound. 

The reliever’s velocity was down across the board and he had been dealing with the pec issue for the last few days, Boone said after the game. 

“We don’t think it’s too serious,” Boone said. “We feel like it’s probably just a couple-day thing.” 

In his first appearance since Sunday, Cousins’ first two pitches were concerning. He threw a 90.4 mph sinker (down from his season average of 95.1) and then plunked Josh Rojas with a 91.8 mph fastball (down from his season average of 94.9). 

Cousins then threw four sliders to Rodriguez to strike him out, but they averaged 80.9 mph, down from his season average of 82.1. 

At a time when the Yankees are mixing and matching in the late inning without a set closer, Cousins has emerged as a valuable high-leverage arm. He carried a 2.39 ERA into Thursday, with 52 strikeouts in 37 ²/₃ innings. 

Luke Weaver has looked the part of a closer in the two weeks since the Yankees opened up the job. 

But he may not get the official title — or strictly ninth-inning duties — heading into the postseason, regardless of how well he pitches. 

Boone has mixed and matched his relievers in the late innings since removing Clay Holmes from the closer role and indications are that will continue into October. 

After throwing 1 ²/₃ scoreless innings on Wednesday to send the game to extras — where the Yankees won 2-1 in 10 innings to clinch a playoff spot — Weaver had tossed 7 ¹/₃ scoreless innings with 16 strikeouts and three walks across his last five appearances, which included two saves. 

Asked on Thursday if Weaver had done enough to claim the closer’s job, Boone declined to anoint him. 

“It may turn out that Luke Weaver’s closing a lot of games,” Boone said Thursday morning. “But it may turn out that Luke Weaver comes in in the biggest game in a spot in the sixth inning and gets four or five important outs when the game’s on the line. 

“One of the things I love about the group down there is I feel like a lot of them are really throwing the ball well and really capable and high-leverage in the back end. And, just as important is I feel like they’re very complementary of one another, meaning what they do well, who they get out well. That’s what I’m looking at is getting them in the right posts. Luke certainly is obviously one of the central figures down there.” 

Weaver entered Wednesday’s game right after Holmes had hung a slider to Justin Turner, who crushed it for a game-tying home run.

It marked Holmes’ league-leading 13th blown save of the year, tying the franchise record (held by Dave Righetti and Goose Gossage). 

But Boone continued to throw his support behind Holmes, saying he has been “snakebitten by the mistakes he’s made.” 

“I think [his confidence is] way better than all the speculation that I’m sure is swirling out there,” Boone said. “The reality is he’s still really good and his stuff is really good. He’s going to get big outs for us.” 

After holding just a champagne toast when they clinched a playoff spot in 2022 — followed by a raucous champagne-spraying celebration when they won the division — the Yankees went straight to the full celebration Wednesday when they wrapped up the AL’s first postseason berth. 

“I think it was just important to everyone that we celebrated getting to the postseason,” Boone said. “Simple as that. Every one’s different, every moment’s different, every time you do it is different. I don’t think there’s any right or way. You just try to live in the moment with it a little bit and that’s how we went about it.”