This is a mentality the Islanders haven’t had in a long time. Instead of bracing for what it means to be Stanley Cup contenders, they should embrace it and go all in.

As general manager Garth Snow readies for the first round of the NHL draft Friday, he has to figure out how best to utilize his No. 19-overall pick. With not another pick until the fourth round, this is not an Islanders draft of old, where prospects were being stockpiled and Snow’s phone was on silent.

The franchise now is ripe with prospects — some good, some not so good. Does it make sense to add another that won’t mature for another couple years, or would it make more sense to put that pick in a package with one of those overflow prospects in hopes of getting that perpetually absent top-line winger?

You can’t force a good trade, and maybe the best move will be to keep the pick, but the priority has to be the here and now, not the future.

What has become clearer in the month since the Isles lost to the Lightning in the second round of the playoffs is there will be a void next to John Tavares — if there ever was a rock. Kyle Okposo, the career-long Islander, almost is assuredly going to leave for greener pastures come the opening of his unrestricted free agency July 1.

On the radio last week, Snow made that rather clear.

“Kyle’s a great person,” Snow said. “He’s been a terrific player for this organization. Wish him nothing but the best.”

It seems as though fourth-line hit-master Matt Martin will be leaving, as well. Even though the Players’ Association agreed to the 5 percent salary-cap escalator, raising the ceiling from $71.4 million to an even $73 million — and thus more escrow taken out of their paychecks — Snow is wisely considering any raise on Martin’s previous $1 million a year deal to be too much.

Also smartly, it seems all signs are pointing to Snow getting closer to an extension with Frans Nielsen, the indelible 32-year-old center who was just named captain of Team Denmark in the Olympics qualification tournament in September. Good. Nielsen is needed at both ends of the rink, and his leadership for this young squad would be desperately missed.

But Nielsen cannot carry the offensive load behind Tavares. There needs to be more high-end talent. There needs to be maturity from the likes of Ryan Strome and Brock Nelson and more consistency from Anders Lee, who is coming off a broken leg. The franchise needs to know who among young defensemen Ryan Pulock, Adam Pelech and Scott Mayfield is worth keeping and who can be jettisoned.

Really, what Snow and his staff need is to make hard decisions about each one of those young players. They can no longer hope that potential is going to be fulfilled. They have to decide now in whom they believe and in whom they don’t. Whoever ends up on the outside of that circle should be actively shopped for a proven NHL commodity.

The Islanders no longer have the luxury of time. Tavares is signed for another two years on his ridiculously club-friendly $5.5 million annual cap hit, and as much as he likes it here, don’t think a disappointing season caused by Snow’s inaction won’t bother him and push him toward Lou Lamoriello, Mike Babcock and Friday’s assumed No. 1 pick of his hometown Maple Leafs, Auston Matthews.

And don’t think new owners Jon Ledecky and Scott Malkin feel obliged to keep dear any sort of agreement with Snow’s job security that was granted under the receding stewardship of Charles Wang. Consider the same pressures to be on the shoulders of highly underpaid coach Jack Capuano.

The reality is the Islanders are a win-now team. It’s been a long, dark road to get here, but they’re here. They need to recognize that and go for it. Anything less than all-in would be a disservice.