The Oklahoma City Thunder and center Isaiah Hartenstein agreed to a three-year extension through the 2028-29 season, sources told ESPN's Shams Charania.
Hartenstein's new contract includes $75 million in new money, bringing his total guaranteed earnings with the franchise to $134 million over five years, according to Charania.
The deal replaces a $28.5-million team option in his previous contract and reportedly includes a unique mutual option that allows the two sides to rework the agreement in 2028.
Hartenstein, 28, initially joined the Thunder as a free agent in July 2024, signing a three-year, $87-million contract.
He averaged 9.2 points, 9.4 rebounds, and 3.5 assists on 62.2% shooting across 47 regular-season contests in 2025-26 but missed a significant portion of the campaign due to left leg injuries.
