This is the kind of deal Ainge likes doing, much in the style of Crowder and Isaiah. If he hasn't pulled the trigger now means he has a plan, whichever is it (getting a big free agent in summer, trading for a greater player, etc). Trust him.
Sorry if someone has stated the same point, I am so surprised by the trade (Portland gets a lot for a little) that I have been inclined to write and then read, a bad thing.