Celtics president Danny Ainge has additional evidence to present.
Chris Forsberg of NBC Sports Boston:
Morris came out ahead this season. He’s earning $15 million on a one-year contract with the Knicks. The highest 2019-20 salary Boston could’ve offered in an extension was $10,605,600.
The Celtics could’ve guaranteed Morris an additional $19,362,144 over the next two seasons (a total of $34,362,144 on a three-year extension). But we don’t know whether Boston offered the highest-possible amount. So, we can’t determine whether Morris will come out ahead financially.
This also barely addresse Morris’ point: After a productive season with the Celtics, he’s bothered they didn’t even reach out during free agency. It’s not about whether or not they once wanted to keep him.
To be fair, Boston did well to use the cap space vacated by Morris and Al Horford to acquire Kemba Walker. Also re-signing Morris would’ve likely required signing-and-trading Kyrie Irving – a possibility, but one that would’ve required sending the Nets a sweetener. That probably wasn’t worth it considering the Celtics have several other key forwards in Jayson Tatum, Jaylen Brown and Gordon Hayward.