Slow down, young buck. Time really is on your side.

In more ways than you know, Matt Harvey.

Sandy Alderson made it crystal clear Tuesday night at Citi Field that the Mets’ young ace will spend the rest of the season on the sidelines and in the bullpen, there is just too much to risk accelerating Harvey’s rehab from Tommy John surgery, especially in light of Jeremy Hefner’s terrible arm injury during his Tommy John rehab.

And the Mets general manager is correct.

“Just a tough, tough development for him,’’ Alderson said of Hefner, before spinning the story forward to Harvey.

“We’re disappointed for [Hefner] and he worked hard to get back to where he was; his is a cautionary story for others, including Matt Harvey, I think,’’ Alderson said. “So while Jeremy’s occurrence is unusual, it points out that those kinds of things can happen. If nothing else, what may come out of it is that others, including Matt and others may be a little more careful about how aggressive they become in their rehabilitation.’’

Alderson might as well have said: “This seat on the bench is for you, Matt.’’

It all is for his own protection.

The Mets can never forget, though, that Harvey is a different animal. He is more competitive than every other pitcher in their system. So while they are right to slow him down to make sure time does heal his pitching wounds, they also must be careful not to frustrate him to no end.

Ultimately, time is on Harvey’s side.

In the big picture, Harvey becomes a free agent in 2019 and if he does not like the way this ballclub is run, he will jump to the Yankees or some other team.

The Mets need to get Harvey completely healthy, keep him healthy and let him be the heart and soul of this team and build around him in such a way he wants to remain a Met his entire career.