SEATTLE — When the idea of ​​a career-changing and ultimately career-shaping transition was first presented to him nearly a decade ago, Edwin Diaz hesitated.

He was a starting pitcher in the minor leagues. Starting pitchers love being starting pitchers. In May 2016, the Mariners decided they wanted him to be a relief pitcher. Diaz didn’t like the idea until Seattle’s decision makers made it clear that such a switch would quickly move him to the majors.

That incident, which Diaz recalled fondly Friday afternoon, set off a chain of events that shaped him into the man he is today: a pillar of the Mets and the owner of the largest relief contract ever, someone proud of the work he has done in his first return to Seattle since the big trade that sent him to Queens in late 2018.

“It feels good to be back,” Diaz said before the Mets’ series opener with the Mariners. “I have some really good memories here.”

In broad strokes, Diaz’s time with the Mets has been similar to his early career with the Mariners: utter dominance (2018 with Seattle and 2022 with New York) and, at times, profound failures that temporarily cost him the closer’s role (2017 with Seattle and 2019/2021/2024 with New York).

But it’s worth noting that Diaz is also back to his best form since returning from the injured list in mid-June: 1.38 ERA, 0.86 WHIP, 16 strikeouts in 13 innings. What impressed first-year Mets manager Carlos Mendoza most was “the consistency of his personality.”

“He’s the same guy,” Mendoza said. “Especially when it was tough for him, he was the same guy. He wanted to be there… The most important thing is the ability to keep going after a tough outing or a tough period.”

How would Diaz sum up his Mets career for Mariners fans who haven’t followed him closely in the other league?

“My time with the Mets didn’t start out the way I wanted it to,” he said. “I got traded and didn’t perform the way I wanted to, but after that year I went home and realized I needed to work harder. After that season everything just worked out. I was able to perform the way I wanted to in New York. If they see the numbers and everything, they can see that I can do my job.”

This trade, of course, comes after Diaz’s success in 2018.

A walk down memory lane: The Brodie Van Wagenen-led Mets acquired Diaz and Robinson Cano for a package of five players, including then-top prospect Jarred Kelenic, Jay Bruce, Anthony Swarzak, Justin Dunn and Gerson Bautista.

Diaz and Kelenic (currently in Atlanta) are the only players still playing in the majors.

He said Diaz continued to meet with Cano once a week.

“I told him, ‘No matter where you go, if I go with you, I’ll be fine,'” Diaz said after learning of the trade. “I was lucky to get traded to New York with him.”

The Mariners have another young, hard-throwing, game-saving strikeout machine in Andres Munoz, who was named an All-Star for the first time last month.

Diaz and Munoz were introduced by Mariners bullpen catcher Fleming Baez, who had long been a protégé of Diaz, during Seattle’s 2022 trip to Citi Field. Munoz approached the improved Diaz and Baez made it happen.

“He asked me how I prepare for a fight, how I deal with it when things don’t go my way,” Diaz said. “It’s going great.”

Notes and quotes: Starling Marte will report to Double-A Binghamton on Sunday to continue his rehab assignment in the latest indication that he is nearing a return from a right knee sprain that has sidelined him for a month and a half. “Hopefully it’ll be during home games,” Mendoza said. The Mets are in New York for nine games starting Tuesday. Christian Scott (right elbow sprain) has not continued to throw. He is asymptomatic, according to Mendoza, but the Mets are taking time to regain his strength before resuming baseball activity. The Mets have not activated Reed Garrett, but he has returned to the team with a physical. They plan to bring him back from the IL in the next day or two, as bullpen needs dictate.

Tim Healey is a Mets reporter for Newsday. Born on Long Island and raised in Connecticut, Tim previously worked for the South Florida Sun Sentinel, the Boston Globe and MLB.com. He is also the author of “Hometown Hardball,” a book about minor league baseball in the Northeast.