SEATTLE -- At the start of the regular season, Shea Langeliers, Cristian Pache and Nick Allen were regarded by MLB Pipeline as three of the top five prospects in the A’s farm system. Six months later, that trio has graduated to the big leagues, providing the A’s hope for a brighter future.

Langeliers, Pache and Allen supplied all the power for the A’s in Sunday’s 10-3 victory over the Mariners at T-Mobile Park, highlighting Oakland’s 12-hit outburst by combining for four home runs and six RBIs.

“It’s a great day for the young kids,” said manager Mark Kotsay. “We talk about the future. Allen, Pache and Shea had the majority of the offense today, which was nice to see.”

Two of those big flies belonged to Langeliers, marking the first multihomer game of his career. The catcher opened up the scoring when he led off the fourth inning with a towering 423-foot solo shot into the second deck off reigning American League Cy Young Award winner Robbie Ray. Later in the ninth, he capped Oakland’s run production by lining a three-run homer over the left-field wall.

The immediate success Langeliers enjoyed upon receiving his first Major League call-up on Aug. 16 was followed by struggles as pitchers began to make adjustments and identify holes in his swing that have led to a high strikeout total. While refining his approach remains a work in progress, Langeliers, now hitting .222 with six home runs and 20 RBIs through his first 37 games as a big leaguer, has provided enough glimpses for the A’s to maintain their optimism about his major potential with the bat.

“I’ve been working every day with [A’s hitting coaches Tommy Everidge and Chris Cron] on really just nailing down my approach,” Langeliers said. “I’m starting to feel really comfortable and confident at the plate. That ability to stick to your approach and have the confidence to not do too much and just be who you are at the plate, it feels good.”

Allen’s fourth home run of the year -- a two-run blast off Ray with two outs in the sixth – was his first home run since Aug. 15. His shining moment, however, came one inning prior on defense, when he turned in a late-season entry for Play of the Year.

In the bottom of the fifth, Allen ranged to his right into shallow left field and fully extended his left arm while diving to pick a hard-hit grounder in the air. Spinning while quickly hopping back up to his feet, the shortstop fired a perfect throw to first, taking away a hit from Mitch Haniger for a brilliant inning-ending gem.

“It was crazy,” Langeliers said of Allen’s play. “Into the six-hole and bounced above his head. He was diving and the ball just disappeared. He snagged it. It was one of those plays where it’s like, ‘Oh, that’s a base hit. Wait, no it’s not.’”

Having earned a spot on MLB Pipeline’s All-Defense first team for three straight seasons from 2020-22, Allen’s elite defense was on full display. Though it would have been a spectacular play under any circumstance, Allen took greater pride in that it came at a point in the ballgame in which A’s starter James Kaprielian had yet to allow a hit against Seattle.

“Right before, I was like, ‘I’m making any play possible right now to help out Kap,’” Allen said. “He had no hits up there, so anything close to me, I’m going to get. Ball was hit, I went for it and it kind of went up. I put my glove up there and felt it in my glove. I was already spinning correctly and then I was saying something while I was spinning. I planted [my feet] and I think I said, ‘Fire!’ and just threw the ball. I thought it was pretty cool.”

Kaprielian, who took a no-hitter into the sixth and held Seattle to one hit and two walks with seven strikeouts over six shutout innings, was in awe of Allen’s effort as he watched from the mound.

“Unbelievable,” Kaprielian said. “It was awesome. Just a taste of what Major League Baseball is going to get from him the rest of his career. He’s just giving people a taste right now.”

For Kaprielian, Sunday’s outing marked his last in what has been an up-and-down sophomore 2022 campaign. Holding a 4.23 ERA in 26 starts on the year, the right-hander encouraged the A’s with his strong finish, posting a 1.80 ERA in 25 innings over his final four starts.

“It’s been a tough year for myself,” Kaprielian said. “It wasn’t the year that I wanted. But I could say positively that I did learn a lot this year. The numbers aren’t going to show. But I learned a lot about myself. A lot of things that I’m going to digest and look back on. It’s a step in the right direction. ... I’m excited about the way it’s finished.”