Navigating Isaiah Hartenstein dilemma at center of Knicks’ uncertain free agent position

The heavy lifting is presumably done already for the summer. The Knicks made their big trade for Mikal Bridges , then they re-signed their biggest free agent in OG Anunoby . It’s always possible another giant trade is completed before next season. As far as free agency — which starts at 6 p.m. Sunday — the Knicks have no cap space and are navigating the NBA’s new restrictive apron system.

It’s all very complicated but, for the purposes of free agency, there’s a chance the Knicks will be a second-apron team (the most restrictive) and have no access to any mid-level exception. That means they can only sign players to minimum contracts. If they’re a first-apron team, the Knicks can use the taxpayer mid-level exception, which projects to be worth $5.2 million in 2023-24 salary. Not a lot of options for that price in today’s NBA.

Also, the Knicks’ rotation is pretty full. There’s a big question at center (we’ll get into that in a moment), but they’re solid through eight players. All these guys are under contract next season: 1. Jalen Brunson, 2. Julius Randle, 3. Bridges, 4. Anunoby, 5. Mitchell Robinson, 6. Josh Hart, 7. Donte DiVincenzo, 8. Miles McBride.

DiVincenzo led the Eastern Conference in 3-pointers last season — by a wide margin — and he’s No. 7 on this list. If one of New York’s four draft picks pop — or if Jericho Sims takes a giant leap — you’re looking at an impressive nine-man rotation.

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Could it still be better? Yes. How? Re-signing Isaiah Hartenstein. His free agency is the biggest Knicks question heading into Sunday, and the answer is multi-layered.

The discussion starts with the idea that the Knicks can offer Hartenstein no more than four years, $72.5 million with his Early Bird Rights. Not long ago, that was viewed as more than enough to secure a player who never averaged more than 8.3 points per game. But Hartenstein blossomed last season following the ankle injury to Robinson, exhibiting his trademark toughness with a reliable floater and an expanded offensive repertoire. He’s now probably the best center in a weak free agency class during a booming NBA economy.

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One of Hartenstein’s would-be competitors in the market, Nic Claxton, just re-signed with the Nets for a whopping four years, $100 million . That’s a good omen for Hartenstein’s bank account. The expectation, as a source reiterated this week, is that Hartenstein will receive offers above what the Knicks can muster. The Thunder, as The Post reported, is viewed by NBA sources as a dangerous suitor, and the Magic have also emerged as a threat. Those two teams — plus the 76ers, Pistons, Spurs and Jazz — have enough salary-cap space to overwhelm New York’s max offer.

Hartenstein is known to enjoy New York and his teammates. His fit in Tom Thibodeau’s system — though rocky at first — elevated Hartenstein’s game and stature to a level he’s now commanding this lucrative attention. A four-year deal from New York offers stability in a place he’s comfortable, having just become a first-time father this month. There’s a world where Hartenstein takes less money — or, at least, less average annual salary — to re-sign with the Knicks.

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But the Knicks also have to maneuver just to get to the point of offering Hartenstein something reasonable. As it stands with the current iteration of the Bridges trade — which can be altered before it becomes official — they’d be hard capped at the first apron and unable to free up the four-year, $72.5 million max.

That hard cap would be a result of receiving more salary in the Bridges trade than they’re giving Brooklyn. One way to alleviate that would be to add McBride and his $4.7 million salary to the trade. A source said the Knicks were set on agreeing to McBride’s extension in December last season because it takes six months until he’s eligible to be traded. McBride’s extension was official on Dec. 30, and six months later is Sunday — the opening of free agency. Not a coincidence.

Still, McBride became such an important part of the Knicks success last season that it’s tough to envision team president Leon Rose dumping him to Brooklyn without a guarantee that Hartenstein is re-signing. Other possible maneuvers to free up the flexibility to re-sign Hartenstein include trading Robinson, using Precious Achiuwa in the Nets deal with a sign-and-trade, or somehow combining the contracts of the second-round picks the Knicks just drafted. It’s complicated. Even then, it doesn’t matter if Hartenstein accepts a more lucrative option.

And starting Sunday, he can begin formally receiving those offers.

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