SEATTLE – On the eve of his major league debut, as he unsuccessfully tried to get some sleep, Cole Young’s mind raced through all the various scenarios he might find himself in the next day.

But there was one situation that never crossed his mind.

Perhaps because it would’ve seemed too good to be true.

Young delivered a walkoff in the 11th inning of his first big league game, chopping a grounder to first base that brought home Miles Mastrobuoni for the winning run in the Seattle Mariners’ 5-4 victory over the Minnesota Twins on Saturday evening.

“That was unreal,” Young said, still trying to grasp the dream-like whirlwind that had just ensued. “I can’t even describe it. The past 24 hours, it has been insane. I mean, I never thought I would be in that situation hit a walkoff in my debut. That was unreal.

“I didn’t sleep last night,” he added. “I was just thinking of every scenario that could happen, (but) a walkoff was not in my mind.”

Young also picked up his first career hit in the ninth inning. After falling behind 1-2 against Minnesota reliever Griffin Jax, Young dipped down and pulled a low-and-inside sweeper into right field for a single.

And in the 10th, Young helped turn an inning-ending double play that prevented a run from scoring.

It was all part of a highly impressive debut for the 21-year-old second baseman, who was promoted earlier in the day after a scorching month in Triple-A Tacoma, where he hit an astounding five home runs, three triples and 10 doubles over his final 24 games.

“He’s a big league player,” Mariners manager Dan Wilson said. “That’s why he’s here, and he made the plays. He did an outstanding job. And that’s not easy to do when it’s your first big league game.

“He was able to go out there and just be Cole Young. It’s just an outstanding ballgame for him and it led to a big win for us.”

Young, ranked as MLB Pipeline’s No. 43 overall prospect, was drafted by the Mariners as a first-round pick out of high school in 2022. He was highly productive at every level of the minors, all while being one of the youngest players at every stop.

Young was widely expected to reach the majors at some point this season. And after his recent tear in Tacoma, his promotion began to feel inevitable.

But still, Young was caught off-guard when he was pulled in the middle of Tacoma’s game on Friday night.

“Our manager came up to me after the third inning and he was like, you’re going to Seattle tomorrow,” Young said. “And I had him repeat it. I’m like, what? Because I couldn’t believe it. And then he told me (again).

“And so last night I didn’t sleep at all. I was just thinking about what would happen today.”

When Young came to the plate in the 11th inning, the winning run was on third with one out. He fell into an early hole, fouling off three of the first four pitches from Minnesota reliever Cole Sands.

Young then got his bat on a 1-2 splitter and sent a one-out chopper to former Mariners first baseman Ty France. France barehanded the ball and threw home, but Mastrobuoni slid in safely.

It was actually stunningly identical to Young’s walkoff on Thursday night in Tacoma, when he hit a high chopper to first that plated the winning run for the Rainiers.

“It was like the same exact hit, which is crazy,” Young said. “I’m just glad I put the ball in play and good things happen.”

After his walkoff on Saturday, Young was mobbed by his new teammates in shallow left field. Meanwhile, his family and friends celebrated from the T-Mobile Park stands, along with some 37,000 other ecstatic Mariners fans.

“I still haven’t wrapped my head around the game,” Young said, “but it’s been an unreal 24 hours.”

More on the Seattle Mariners

• Cal Raleigh moves into tie for MLB HR lead, then fire alarm goes off
• Cole Young to make MLB debut, start at 2B for Seattle Mariners
• Three reasons behind the Seattle Mariners’ May swoon
• Seattle Mariners prospect Harry Ford continues tear with massive HR
• Seattle Mariners’ Cal Raleigh details his key improvement at the plate

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