MAVS NEWS:

[F Gump]

I'll bet they extend the deadline, to allow for other signings, trades, and negotiations.

Maybe. But I'm not sure I see why.
1  Isn't an opt out needed for the Mavs to have more workable numbers this year, no matter what? (So what's to decide?)
2 Can't they already have figured out what numbers they are going to do, and the structure, with perhaps some if/then choices for later?
3 They really can't extend it far enough to make much difference - only to Sunday. He can see the draft and whatever happens in that general time frame. But Kyrie can't delay it to get a peek at who Mavs are going to get in free agency (if anyone), trades in free agency time, etc.

The only reason to delay is that he MIGHT want to keep that 43M year, but that really doesn't fit as a realistic possibility with anything we know.