If Jaylen gets All-NBA this year, he’d be eligible for a 6-year extension, which includes the final year of his current deal, at 35% + 8% raises beginning in 2024. If Jaylen gets All-NBA next year, the Celtics, and only the Celtics, could sign him to a 5-year deal at 35% of the cap + 8% raises. He would be eligible for a designated veteran contract instead of a designated veteran extension, but they are functionally the same.
Yes, this is my understand based on what I have read (I can't quote the exact figure like Celtics2021 can though). The only thing I think you can conclude for sure is that if he qualifies for the enhanced
extension (All NBA or whatever), it is offered, and he turns it down, then you know you have to trade him. At that point, you know it isn't about money as the
extension now or the
contract later are "functionally the same" as Celtics2021 explains.
If he doesn't qualify for the enhanced extension, him declining the "regular" extension doesn't mean anything. Any player of his caliber would probably do that. That would not mean he wants out. It would merely mean he has decided to take the chance to wait for a bigger payday. And at that point (when he becomes a UFA), the Celtics would still be able to offer the most years and the most money. They would be in the best position to sign him. So no need to panic and trade him, based purely on him declining the "regular" extension.