Makes sense to me.  What is Chandler Parsons if not an expiring to acquire a high salary player’s Bird rights in a year when few teams have cap space?  Heck, maybe Drummond picks up his player option.
It obviously depends what Atlanta would send out, but a lottery protected pick from Brooklyn is probably something they can afford to give up.  Worst case scenario they’d get something similar back this summer via a S&T if Drummond wants to go elsewhere.