Isaiah Hartenstein plans to sign a new three-year, $75 million contract that will keep him with the Oklahoma City Thunder through the 2028-29 season, according to sources who spoke with ESPN’s Shams Charania on Friday.
His representatives, Andrew Morrison and Aaron Mintz of CAA Sports, finalized an agreement with the Thunder that features a maximum 15% trade kicker and a mutual option allowing both sides to revisit the deal again in 2028 before the final season, sources said.
The contract brings Hartenstein’s total guaranteed earnings with the Thunder to $134 million over five years.
Standing 7 feet tall and weighing 250 pounds, Hartenstein joined Oklahoma City as a free agent during the summer of 2024. He became one of the finishing pieces of the Thunder’s championship puzzle by providing a needed physical presence inside.
Hartenstein, 28, averaged 10.3 points, 10.1 rebounds, and 3.7 assists per game across his first two seasons in Oklahoma City. During that span, he primarily served as the Thunder’s starting center.
Injury interruptions marked his tenure, including a broken left thumb that kept him out at the start of the 2024-25 season. He also managed a right calf strain last season, which limited his total to 104 games played over two regular seasons.
Despite those absences, Hartenstein has appeared in all 38 playoff games for the Thunder in the past two years, starting 35 of them.
In postseason play for Oklahoma City, Hartenstein has averaged 9.1 points, 8.3 rebounds, and 2.6 assists per game.
The new deal gives the Thunder continued stability in the frontcourt and retains a player who has contributed both regular-season and playoff minutes since joining the team.
The agreement also provides Hartenstein and the Thunder flexibility in 2028 through their mutual option, giving both parties an opportunity to rework terms before the contract’s final year.
Andrew Morrison and Aaron Mintz of CAA Sports represented Hartenstein throughout negotiations with Oklahoma City.