Mets pitcher Jacob deGrom stretches at the start of spring...

Mets pitcher Jacob deGrom stretches at the start of spring training Feb. 19, 2016, in Port St. Lucie, Fla. Credit: AP / Jeff Roberson

PORT ST. LUCIE, Fla. — Jacob deGrom’s refusal Friday to sign the Mets’ contract offer sounds much worse than it actually is. As protests go, it’s not as if deGrom is going to be picketing outside Tradition Field, chanting slogans and waving a sign that reads, “Zero to three isn’t for me!”

Is deGrom underpaid at $607,000 this season? Duh. Two months ago, Jeff Samardzija took the Giants for $90 million over five years, but that’s the beauty of free agency. And deGrom won’t be a free agent until 2020.

What happened to deGrom is hardly new, and not all that unusual for a player with less than three years of service time. Just last week, the Pirates’ young ace, Gerrit Cole, also was annoyed at being renewed. The frustration, however, usually fades by the first big payday.

A prime example, staying local, is Derek Jeter, who chafed at the Yankees’ renewal in 1997. Nearly two decades later, Jeter retired in pinstripes after getting $265 million from the Steinbrenner family. We’d say things turned out OK for both parties.

What happened Friday is part of the process under the sport’s salary structure, in which the team wields the hammer for the first three years and the player swings it after that, first through arbitration and then, once he gets six years in, via free agency.

So the Mets, who have the upper hand with their talented young rotation, are going to use that advantage, unapologetically, just as other teams would.

It can sound harsh, and the Mets’ formula for under-three salaries may come off as unfair to someone like deGrom, who is a former Rookie of the Year and All-Star with Cy Young votes on his resume. But this is a matter of literally buying time, as cheaply as possible, until the Mets are faced with doing something long term, which then will involve crazy dollars. Right now, there is zero pressure for the Mets to do so, and deGrom understands that. Even if he doesn’t like it, as reflected by Friday’s action.

“It was a decision based on the business side,” deGrom said.

The Mets boosted their 2016 payroll to $140 million with the late signing of Yoenis Cespedes, the most they’ve spent since 2011. Fortunately for them, Matt Harvey is the only member of the rotation to make it to arbitration, and they settled with him for $4.33 million — still a comparative bargain.

The clock is ticking, however. Harvey will become a free agent after the 2018 season, and then the dominoes will start falling, with deGrom two years later and eventually Noah Syndergaard and Steven Matz. But we’re talking way off in the distance here. The Mets don’t need to do anything yet with these pitchers, so they won’t.

That could change, of course, if the two sides can agree on maybe buying out a few arbitration years, saving the Mets a few million while providing some early guaranteed cash for the young guns, four of whom already have had Tommy John surgery. But remember: They’re not going anywhere.

“Right now, I’m focused on the present,” general manager Sandy Alderson said Friday. “I’m going to enjoy these guys. I’m not going to get too uptight about what might happen in 2020 because there’s plenty of time for us to resolve all that. In the meantime, the most important thing is for those players to perform and for the team to win.”

Good advice. For a few minutes there, Alderson sounded as if he were telling the fans to calm down, take a few deep breaths and appreciate having what arguably is the best rotation in baseball. It doesn’t happen very often. And when a staff like this does come along, the expiration date always feels too soon.

Something usually happens to split them up, be it the Glavine-Maddux-Smoltz Braves or the Hudson-Mulder-Zito A’s. Rotations like that eventually get expensive, or broken, or old. But the Mets are lucky to be in that sweet spot right now, and they’re trying to ride that wave for as long as possible.

“There seems to be a fixation on some of our players and the brevity or length of time with the Mets,” Alderson said. “In all these cases, they’re going to be with us for a while.”

Much longer than any hurt feelings.