New York Mets minor league catcher Francisco Alvarez talks to...

New York Mets minor league catcher Francisco Alvarez talks to the press during practice at Clover Park in Port St. Lucie, Florida, on Feb. 18, 2022. Credit: Octavio Jones

Francisco Alvarez is the Mets’ next “Next Big Thing,” a 20-year-old catcher with prodigious power who the club hopes will be its long-term solution for a position at which it has had little stability and even less production since . . . well, since Mike Piazza.

Among his supporters internally is a perhaps unlikely name: James McCann, the man whose job Alvarez wants.

The Mets’ catcher of the present is a fan of the Mets’ catcher of the future — his skill set, his work ethic, his want.

“I root for him to have success. I don’t root for him to fail. I want him to have success, I want him to have a phenomenal career,” McCann said recently. “I hope that the things I talked to him about in spring training, the things I talked to him about this week, he can take with him in his career. Whenever he does get here, I’m going to be rooting for him. Regardless of my status, I’m going to root for him.”

Given Alvarez’s age (he won’t turn 21 until November) and position (the most defensively demanding on the diamond), reaching the majors is not necessarily a near-term proposition.

But there is some thought within the Mets that he might be their best option at designated hitter down the stretch this season — a scenario that would raise myriad questions, such as how to keep him developing as a catcher if his game duties are limited to batting.

Alvarez is wrecking Double-A pitching with Binghamton. He has a .280/.365/.564 slash line with 17 homers, 16 doubles and 45 RBIs in 62 games, dominating a league in which the average player is four years older than he is.

McCann witnessed a portion of his particularly torrid June during a recent rehabilitation assignment. They shared a locker room during the last two spring trainings, but they got to talking more during that week with Binghamton.

Alvarez, according to McCann, was eager to gobble up whatever wisdom the 32-year-old veteran had to dispense. And McCann was happy to oblige.

“As a young player, it’s impressive to me to hear him talk about hitting. Whether it’s regurgitated or not, hearing him talk about his approach off a certain pitcher was impressive,” McCann said. “He wanted to watch me go through my routine and talk to me. We’d sit there on the bench and dissect the other team’s catcher. We’d have the TrackMan in our dugout, there’d be borderline pitches that get called balls and I’d say, ‘See how he didn’t stay underneath that long enough?’ Different things where I was able to pour knowledge into him, and hopefully he can take that and work with it.”

And Alvarez’s power?

“The prospect rankings aren’t a fluke,” McCann said. “There’s very few hitters that I watch in BP that I say, wow, that’s a real power tool. That’s what he’s got, a real power tool. Similar to watching Pete [Alonso] take BP. It’s a real thing.”

Catching, though, is a beast. McCann recalled that when he broke into the majors with the Tigers in 2014, his manager, Brad Ausmus, himself an 18-year major-league backstop, told him that the most meaningful learning happens on the job. And it isn’t fast.

McCann shared Ausmus’ sentiment with Alvarez.

“It’ll take you three or four years before you really understand calling a game at this level,” he said. “It doesn’t matter how much homework you do, how much help you have from the dugout. It takes that experience of getting burned in a game by a guy and then logging it in the memory book to then two years down the road say, ‘I’m not getting burned the same way I got burned two years ago.’ That type of stuff.

“But the tools are there. I joked with [Alvarez] and said if he was a leftfielder, he’d probably be in the big leagues. They wouldn’t be talking about his defense.”

The tricky part for McCann and maybe the Mets is that his contract, at an average of $10 million per year, runs through the 2024 season. Barring the unexpected, Alvarez will be ready for The Show well before then.

McCann isn’t sweating it, he said. He once learned from Alex Avila, then Detroit’s veteran catcher, and eventually supplanted him. Such is the baseball circle of life. Veteran mentorship can be “a lost art” in clubhouses, McCann said, but he wants to do right by the next generation.

“I think he understands just what kind of player he has the potential to be,” he said. “I’m comfortable in who I am as a player. I know that he has a lot of talent. But [getting replaced] doesn’t even cross my mind.”

Notes & quotes: The Mets made several roster moves on their off day Monday, including sending reliever Colin Holderman to the minors and claiming infielder Kramer Robertson off waivers from Atlanta. They also moved righthander Tylor Megill (right shoulder strain) to the 60-day injured list.