OKLAHOMA CITY (KFOR) - By definition, he's the biggest free agent signing the Oklahoma City Thunder have ever signed. Isaiah Hartenstein has agreed to a three-year deal worth $87 million dollars, that per ESPN. The largest free agent deal OKC has ever dished out. Hartenstein joins OKC after spending the last two seasons with the New York Knicks. The Athletic reports that Sam Presti was at Hartenstein's house as free agency began to make the pitch for the 7'0 center to join the Thunder. Hartenstein averaged eight points, eight boards last season all while shooting nearly 65 percent from the field. He provides much needed depth and size for the Thunder who needed it last season. This is Hartenstein's sixth team in the eight seasons he's been in the NBA.