Isaiah Hartenstein decided against returning to the New York Knicks in favor of Oklahoma City.

On Saturday, Thunder general manager Sam Presti announced that the 26-year-old had agreed to the terms of a three-year contract with the team. The deal is worth an estimated $87 million, ESPN reported.

The 7-foot-1 center and his wife, Kourtney Kellar, recently celebrated the birth of a baby boy. The couple and their newborn son received a warm welcome from Hartenstein's new team when they arrived at Paycom Center over the weekend.

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Isaiah Hartenstein smiles before a game

Isaiah Hartenstein #55 of the New York Knicks smiles before the game against the Chicago Bulls on April 9, 2024 at United Center in Chicago, Illinois.

Kellar shared a heartfelt post about the family's experience with the Thunder organization.

"Weekend in OKC I’m still in awe over all the little details that were thought of to make our family feel so welcomed! Thank you for your generosity @okcthunder Looking forward to joining the thunder family," Kellar captioned a social media post showing photos and videos, along with a thunder up hashtag.

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Hartenstein and Kellar tied the knot in 2023 in California. Earlier this year, they announced that they were expecting their first child. 

Hartenstein's parents and his sister were on hand for the special welcome at the Thunder's home arena.

Isaiah Hartenstein looks on court

Isaiah Hartenstein #55 of the New York Knicks looks on during Game Five of the Eastern Conference Second Round Playoffs against the Indiana Pacers at Madison Square Garden on May 14, 2024 in New York City. The Knicks won 121-91.  (Sarah Stier/Getty Images)

Kellar also shared photos from on board a private jet and a balloon display which read, "Welcome Hartensteins."

New York Knicks player boxes out during a game

Isaiah Hartenstein #55 of the New York Knicks boxes out during the game against the Cleveland Cavaliers during the 2023 Round 1 Game 1 NBA Playoffs on April 15, 2023 at Rocket Mortgage FieldHouse in Cleveland, Ohio. (Photo by David Liam Kyle/NBAE via Getty Images)

Hartenstein spent the past two NBA seasons with the Knicks, appearing in all 82 games during the 2022-23 campaign. Last year, Hartenstein suited up for 75 games.

He was in the starting lineup for 49 games over the course of the 2023-24 campaign, averaging 7.8 points and 8.3 rebounds per contest.

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The Thunder will likely enter the upcoming season with high expectations. The team earned the top seed in the Western Conference playoffs this past season after winning 57 games during the regular season. 

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