With Hartenstein’s 28 mil team option he’s basically on an expiring contract just like Simons. With the emergence of Chet he has proven to be the Thunder’s future franchise starting center. Simons helps give them a 2nd scoring punch next to SGA and can play off ball with a very reliable 44 3P% from the corner this season. Player for player this trade makes sense, the only possible obstacle I could see in this trade is the compromise in draft capital asked vs actually given by the Celtics.