It's all about minutes. If he was here and playing then he'd want to stay. The opportunities to prove himself are just too few and far between. And I'm sure you wouldn't like it either if you were in his situation. He's not some 18 year old kid, he's 24. He probably feels like his prime bball years are ticking away and he's got nothing to show for it. Not to mention he's essentially playing here for free because the Pistons organization convinced him to come here earlier than he had planned (and he had to pay his own buyout).