Mills missed the end of his college season with a hand injury. He broke his foot in Minicamp for the Blazers prior to Summer league.
If the issue is an injury he suffered on the Blazers' time - then the team did the right thing in taking care of him. (same with Pendergraph)
The Blazers do not currently need any of those three for anything beyond practice fodder. Mills is the only one with any future value. I have a hard time believing KP is not fully in support of this decision.