Even if he didn't have he no trade, his contract pretty much prevents that. There isn't a contender out there that's going to rearrange their roster to fit Melo on there...especially when he can't stay healthy.
This is my larger concern.
Not so much the contract, which this summer will render closer to reasonable -- but the fact that he's hurt, again.
He's getting old and injured at a time where you would need him to be balling if you were hoping to trade him. This was actually my larger concern last season, when people were in the grips of fighting about melo. He has had some great games, and some great stretches this season, playing complimentary basketball, scoring when he needed to, showing more effort on D, and really orchestrating ball movement as often as he stops it.
But he's hurt again. This will be his FOURTH full-length season with the knicks, and there has only been ONE where he hasn't missed significant time.