Sign-and-trades have to work for three parties with varying interests, so I have a tough time taking those into consideration as viable. In the scenario with Boston, I'm not sure how attractive Boston is without getting Butler (but I'm also not sure Hayward would love to play with Butler). If they have to get Butler first, it limits their ability to offer Hayward their max, so I guess in this scenario there is something to play with. I'm just not sure how the salary-matching would work.
I guess in that specific scenario, there is cause for exploring the idea.
I guess in that specific scenario, there is cause for exploring the idea.