This is the type of move that Auerbach would make. It actually makes sense for both teams.
Of course, another option would be the number 1 pick (via Brooklyn) for Smart or Bradley,
for the 3 and 7.
Likely, Ainge has to decide on IT and Bradley. With Horford's contract, and Boston looking for a major free agent, it makes sense to consider what players fit into the long term plans.
OKC went through this with Harden. And while they didn't get bank- for him, they had to make a move.
Simmons, like the players in the draft is still an unproven commodity. While Avery Bradley is a feisty defensive guard, who can hit a 3 and make plays. He is an asset to whatever team he is on, and a veteran presence.