The Mets’ main question to Francisco Alvarez comes with complex answers

The Mets — health permitting, of course — have a very locked roster.

There are some questions about the optional relievers who will fill the back of the bullpen and whether they could add a second left-hander to join Brooks Raley. But leading pitchers and hitters are defined, fitting for a team that expects to have a payroll of $365 million (for luxury tax purposes), even before calculating the tax.

The only significant mystery is whether young receiver Francisco Alvarez can make an impact from the start and, if so, in what role. In many ways, it revolves around this question: Are the Mets just saying they believe in Alvarez as a defenseman despite the industry’s many doubts, or do they really believe it?

Because it’s not like the Mets are clearing an unfettered path for Alvarez to catch in 2023. Yes, they traded James McCann, who was under contract through next season — and paid nearly 80% of the $24 million owed to him to facilitate the deal in Baltimore. But then they signed two catchers until next year. Free agent Omar Narvaez has a player option for 2024. Tomas Nido was signed for the final two years in control of the Mets team.

So, do words and actions match? Billy Eppler insists they do.

“Yeah, I believe he’s a catcher,” the Mets general manager said by phone. “Because I have internal data that shows improvement and strong receiving ability from Double-A, and that was good from his limited time at Triple-A.”

Saying he “doesn’t believe in absolutes,” Eppler wouldn’t dismiss Alvarez kicking the Mets out of spring training, with the club carrying three receivers. The balance would be making sure Alvarez catches enough (say twice a week) to continue his progress in that area while still using him a few times a week as a designated hitter. For this scenario to come to fruition, Alvarez would almost certainly have to produce a spring training of raucous batsmen while showing continued catching maturity.

What if it was just the bat? What is the balance for a contender between using this tool in the majors and wanting to keep working on defense?

“I’m not going to say one way or the other; I wouldn’t say if I thought his bat was ready,” Eppler said. “I’m going to let time and the evaluation process organically allow that to happen.”

But because he leads baseball operations for the most all-in team of 2023, Eppler couldn’t bet on Alvarez’s overall preparation. So the Mets built a left-right hitting tandem with solid catching skills in Narvaez and Nido. The industry is obsessed enough with the pitch frame that the Mets know they can always trade the cheap Nido (two years at $3.7 million) if Alvarez earns a bigger share of the catch.

The biggest obstacle to Alvarez might not be Naravez and Nido anyway. It may be an age-old problem. Alvarez will play the 2023 season at age 21. Since 1937, only seven men 21 or younger have started at least 100 games in an MLB season at catcher: Joe Torre (1961), Tim McCarver (1963), Bob Didier (1969), Johnny Bench (1968-69), Ted Simmons (1971), Butch Wynegar (1976-77) and Ivan Rodriguez (1992-93). So three of the last four to do so are Hall of Famers (Bench, Simmons and Rodriguez), and it hasn’t been done in three decades.

And it comes at a time when more has been put on catchers than ever before – including more individualized plans for attacking each batter and greater pitching speed and movement to manage and present as strikes. Eppler began to become a strong believer in framing when he watched pitchers gravitate to Jose Molina rather than Jorge Posada from 2007 to 2009 when he was with the Yankees. As Brian Cashman’s assistant general manager after the 2010 season, Eppler pushed hard for the Yankees to sign Russell Martin because of his catching acumen.

Maybe the Mets could slow down Alvarez next year. Owners will likely approve, at their meetings next month, the installation of the automated ball/hit system at all Triple-A venues. If this trial goes well, there will be a chance for robot umps in the majors in 2024. In this case, the importance of call and play throwing would increase, as framing would have no bearing on a robot ump. That would take some weight off a growing young receiver.

Or is Alvarez the rare receiver, like Bench or Rodriguez, who can handle at this age a position that Eppler says “has the most responsibility on the field” – and do it for the most expensive team of them all the temperature?