In a matter of minutes, Kyle Seager went from enjoying his first off-day in years to digging in for the Mariners’ most important at-bat Thursday night.

With two runners on in the ninth inning of a tie game, Seager emerged from the basement-level batting cages at T-Mobile Park and promptly watched a 96 mph strike whiz by on the inside corner.

“I was kind of like, ‘Uh, I might be in a little bit of trouble here,’” Seager recalled. “So I’m glad it worked out.”

On the next pitch, Seager yanked a single through the right side of the infield, scoring Jake Bauers and giving the Mariners a 6-5 walk-off win over the Rays. For the 11-year-vet Seager, it was his first game-winning pinch-hit. And it was, honestly, not part of the plan.

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“It was really supposed to be an off-day for Kyle Seager,” Seattle manager Scott Servais said with a laugh. “But when you get to that point in the game, and you’ve got your one bullet to shoot, you might as well shoot it.”

Seattle entered its final half-inning with a one-run deficit, facing Rays reliever Pete Fairbanks, who had allowed just two earned runs all year (and none since May 19). Servais told Seager to be ready in case a situation arose with runners on, so Seager descended to the cage for some swings.

Up at field level, Fairbanks dealt a four-pitch walk to leadoff man Dylan Moore. Bauers followed with a single up the middle, and Shed Long Jr. tied the game two batters later by slashing a double to left.

Enter Seager, in place of Taylor Trammell, for the 18th pinch-hit appearance of his career (and first this season). He connected on a fastball over the plate, and pretty soon his teammates were mobbing him at first base.

“Give Seags a ton of credit it,” Servais said. “On an off-day, you kind of shut down mentally and physically ... He stepped up and got the big hit for us.”

The change of plans regarding Seager’s not-so-off-day wasn’t the only switch up for Seattle. Before the game, Jake Fraley was scratched with a nagging hamstring issue (he did enter as a pinch-hitter in the eighth, but Servais said they need to be “careful” with him).

Then, after just two innings, starter Justin Dunn was forced out with right shoulder discomfort. He said he felt it in his warmup, but he believed it was “one of those situations where you’ve gotta be able to throw through some stuff.” After two innings, he felt he could no longer do that. He’ll get an MRI on Friday to determine next steps.

“My concern level is not crazy high,” said Dunn, who was on the injured list with right shoulder inflammation earlier this month. “I obviously don’t like that it’s the shoulder; that scares me a little bit. But the fact that my velo’s the same, my stuff’s the same, it’s all encouraging for me.”

Dunn’s abridged outing meant the Mariners’ bullpen had to cover a lot more of the game than expected. Five relievers combined for seven innings, and though each of the first three allowed a run or two, the game was always within reach.

That granted the Mariners a chance to pull off some ninth-inning heroics, which they did. And of course it was Seager, the longest tenured Mariner, at the center of it. He’s as dependable as they come in Seattle, and can be counted on to show up even when he doesn’t appear on the starting lineup card.

“The important part for me is, A) to be somebody that they want to put in the lineup every day, I think that’s a big part of it,” said Seager, who hasn’t missed a game since 2019. “I think, B) taking care of yourself physically. … You kind of want to be the dependable guy. You want to be the guy that [they] can almost just take for granted that you’ll go out there and do your job.”

Seager has been that guy for over a decade, and that reputation is baked into his legacy with the Mariners. It’s certainly noticed by his younger teammates, too.

“I mean, what can I say? The dude’s a pro,” said Long, a third-year Major Leaguer. “He’s been doing this for so long, like, I expected nothing less than what he did. … Just the way he carries himself as a professional, that’s Kyle.”