Isaiah Hartenstein plans to sign a new three-year, $75 million contract with the Oklahoma City Thunder, sources told ESPN's Shams Charania. The deal runs through the 2028-29 season and includes a 15% trade kicker plus a mutual option allowing both sides to rework terms in 2028. Combined with his original agreement, the 7-foot center now secures five years and $134 million guaranteed.

Hartenstein arrived in Oklahoma City as a free agent in summer 2024 and quickly became the finishing piece for a championship-caliber roster. He filled a glaring need for physical interior presence, averaging 10.3 points, 10.1 rebounds and 3.7 assists over his first two seasons while serving as the primary starting center. His passing from the high post unlocked new dimensions in the Thunder's offense.

Durability remains the only real concern. A broken left thumb sidelined him to start the 2024-25 campaign, and a lingering right calf strain limited him to 104 regular-season games across two years. Yet he has appeared in all 38 playoff contests, starting 35, and posted 9.1 points, 8.3 rebounds and 2.6 assists in the postseason — proving reliable when games matter most.

The structure protects both parties: Oklahoma City retains a proven defensive anchor alongside Chet Holmgren, while Hartenstein gains long-term security with a pathway to renegotiate before his age-31 season. For a franchise built on continuity, keeping the league's most versatile big man on a reasonable number removes a major offseason variable.