JUPITER, Fla. — Dan Warthen smiled at the question. His eyes came alive behind his glasses, his cheeks rose.

Pretty much all that has occurred in his professional life — 35 years and counting — had made Warthen appreciate the question, and he savored it for a few seconds before responding, something akin to a wine lover letting a particularly good vintage swirl around his mouth.

This was the question: Have you pondered what it would mean, what it would look like if all of your starters stay healthy and pitch to their capabilities this year?

When it finally came, this was the answer from the smiling pitching coach of the New York Mets: “It is really nice to be me right now. You know why? Because I think they all will do well.”

Perhaps something like this has not been unleashed on Queens since the Beatles landed at the newly named John F. Kennedy Airport on Feb. 7, 1964. By then, the band was a European sensation. But the Beatles became the Beatles in all the historic ways we know them by coming to the States and changing music and culture and, really, everything.

The Mets’ Fab Four — Jacob deGrom, Matt Harvey, Noah Syndergaard and Steven Matz — have had their version of the Beatles’ British success, a trip to the World Series, already. But what we have not seen is all four healthy and forming a rotation from the outset of a season.

And what if on that first US tour, the Beatles had added Mick Jagger? Well, sometime around midseason, Zack Wheeler is scheduled to join the group, and if we are not going to at least consider the grandest possibilities now in the hope and optimism of spring, then when would we ever?

“The best description I can offer is that every night our opponent would be facing either a [No.] 1 [starter] or, at worst, a 2,” said J.P. Ricciardi, the Mets’ special assistant to the GM. “How can it be better than that?”

We know it probably will not go that way. Baseball history screams how rare it is for one team to have five starters thrive. There will be regression or injury. It is hard to ignore that four of the Fab Five already have endured Tommy John surgery and Noah Syndergaard is high on the list to be next, according to one team that has a proprietary system for trying to judge pitchers at risk for ultimately needing the procedure.

But what if it does go positively — physical health combining with genius at 60 feet, 6 inches away? To foster that parlay, the Mets have tried caution, owing to the extra month of pitching done last year. On Monday, Matz became the first of the Fab Five to start this spring, allowing the Cardinals one run in three innings.

However, even before Monday, a lot of fear had been allayed. As Warthen said: “I was concerned about a hangover. I was concerned about overconfidence. It has been the opposite. This is the most focused group I have ever seen. It is the best prepared group I have ever had. The stuff has been great in bullpens, spots have been hit over and over again.”

To the Mets, that is little surprise when it comes to Harvey and Syndergaard, who actually were getting better as the playoffs wore on last year. But the Mets brass was worried about deGrom, since he carried the largest workload last year plus his stuff appeared to finally fizzle in his final World Series start. But deGrom has looked great, Warthen said. The Mets think the fact deGrom is such a fine athlete — as are the others — that it promotes a repeatable delivery and less overall strain on the arm and body.

Still, the plan is to not push too hard. Wheeler is due back around July, and the fact that Warthen foresaw only 12 or 13 starts for the righty strongly suggests the Mets will go to a six-man rotation when Wheeler returns, at least for a while, before probably moving Bartolo Colon to relief. That will ease Wheeler back into action and potentially throttle back on the other starters’ innings.

Wheeler is the wildest card right now. Stuff-wise, he stands with the best of his rotation mates, but he lacks the command of a Harvey or Syndergaard or deGrom. But how about now if his arm is pain-free?

No team since 1953 has had five guys make at least 13 starts with each having an ERA-plus (which factors in league and ballpark) at least 20 percent better than the MLB average. No team since the 2002 Braves (Tom Glavine, Greg Maddux, Kevin Millwood and Damian Moss) has had four pitchers make 25-plus starts with each having an ERA-plus 20 percent or better than the MLB average.

When told some of the numbers, Warthen smiled that smile again, 35 years of seeing it all. He offered one word for what he saw as the possibility and he meant it for the sport, not for the Mets:

“Frightening.”