Josh Hart can’t help himself.

After he missed the opening Preseason game because he was “nicked up,” the Knicks’ backup forward checked into their exhibition Saturday night and, within 25 seconds, dove into the stands for a loose ball.

Hart tripped over the front row and landed — butt first — on the concrete.

He continued to play and appeared uninjured, allowing the sequence to serve as an endearing reminder, rather than a downer, of Hart’s heart.

Then the 28-year-old sat the entire second half of a 121-112 loss to the Timberwolves at the Garden.

He’s taking it easy after he played for Team USA over the summer.

“I’m getting old, that’s all it is. Just old,” Hart said about the reason for missing the opening preseason game. “The amount of games played. Nothing of note.”

Hart’s preseason debut lasted eight minutes, with three points and one flip over a chair.

His teammates picked up the slack, most notably RJ Barrett, who finished with a game-high 23 points in 26 minutes on 6-for-15 shooting.

Mitchell Robinson provided the game’s highlight by pinning Karl-Anthony Towns’ lay-up attempt against the backboard with a chase-down block.

Evan Fournier, who played extended minutes again, added 15 points on 6-for-10 shooting.

But the Knicks’ reserves, including Fournier, were whooped in the fourth quarter, deciding the result and dropping the home team to 1-1 in the preseason.

Jalen Brunson ramped up a little — elevating from six minutes played Wednesday to 14 on Saturday — but sat the entire second half. Julius Randle added seven points in 23 minutes.

The performance, as a whole, wasn’t as clean as in the preseason opener against Boston.

That was expected since the Timberwolves played their “A” squad — Towns (17 points, 27 minutes), Anthony Edwards (17 points, 27 minutes) and Rudy Gobert (nine rebounds in 22 minutes) — while the Celtics rested their entire starting lineup.