Isaiah Hartenstein reveals how agonizing the decision was to leave Knicks

LAS VEGAS — If the big offer came from a team other than the Thunder, Isaiah Hartenstein would have re-signed with the Knicks at a discount, the center told The Post.

But the combination of a three-year, $87 million deal — with $58.5 million of it guaranteed in the first two years — and a chance for a championship was too difficult to turn down.

“I was going to make sure I was set for the rest of my life,” Hartenstein said. “But then at the same time, if it wasn’t a team like OKC, I would’ve taken a pay cut because I loved it [in New York]. But I now have an opportunity to make that money, make that pay raise, and still compete. I think that was the main factor.”

The Knicks, as Hartenstein confirmed in the interview Monday with The Post, made the biggest offer they could given their cap restrictions — four years, $72.5 million — which is about $11 million less annually than the Thunder contract.

Jalen Brunson participated in the pitch to retain Hartenstein.

“They said whatever we can give you, we’re going to give you,” Hartenstein said. “I talked to Jalen a couple times, Jalen and the guys. They really wanted me back and I really appreciate that. But it was definitely a hard decision. I couldn’t say no to an opportunity like this.”