Would it though? You honestly think that if the Celtics played at a 2 seed level for the next two months, but realized they needed a little more depth, defense, and ball-handling to have a shot at challenging the Cavs and Warriors, that players wouldn't understand them dealing a recently-signed UFA with a season-ending injury for two players who fit the bill of what they need in the moment? You think players would think less of Danny Ainge for doing what he thinks it takes to pursue a title this season rather than "playing the long game"?
And yes, I know they'd never do it, but not because of "their credibility in the free agent market," but simply because Hayward's much more valuable than those two, even after suffering a season-ending injury.