If Kyrie leaves, he’s an idiot. Hayward + Tatum + Brown + Horford + Smart is better than Butler + “very accomplished “ player
Perhaps, Boston should consider making a move to add a Butler.
I've thought about that too, as a deadline thing, but I just don't think it's financially feasible for Boston. My guess is that if Butler was made available at the deadline, at age 29 and with Thibs miles on him, Ainge's offer wouldn't go terribly higher than Smart, Morris, and some mix of picks. However, not only do you potentially have all three of Kyrie, Butler, and Horford all looking for big new deals in the summer of 2019 (plus whatever happens with Rozier), but you also have a new contract for Jaylen, possibly a new contract for Hayward, and discussion of a rookie extension for Tatum coming the following summer.
That's without getting into who moves to the bench in the event that Butler's brought aboard.