Part of it was role - Buffalo had expectations of him being able to perform to the salary he was getting when he arrived. And his first six-to-eight week stretch after coming over from the Jets, he was excellent. And then he hurt something - I've heard it was a hip labrum - and didn't get it surgically fixed and might not have actually done the things needed to rehab it fully the way it was needed. And so then it flared up again and he again didn't do the surgery. And again. And all the while, he's out and about, often not even in town, going hunting and fishing and when in town partying hard. So that went on for a while - years - until finally he was broken down enough that he couldn't handle the minutes. He didn't play well and didn't care about playing well. But he was tight with some of the key people on that team - Eichel, Kane, Reinhart - and they acted as though how they prepped and played actually was sufficient. Hockey was something he was doing seemingly so he could hang out playing cards with the boys.
Then he went off to Toronto and Tampa and he wasn't being asked to play top four minutes. He seems to have gotten a bit more serious about how he cares for himself, finally which is why he keeps kicking around as 3rd pairing/depth guy instead of being paid to be a top pairing player. Good for him for finally figuring that out. It doesn't mean that the years he was essentially stealing from the team I route for has changed my opinion of him as a person though. Worked in charity, raised money for some things... don't care. Not being professional enough to see how his play was a huge part of how bad those teams were nor how at the end they were doing him a favor by trying to play him despite how poorly he had taken care of himself and yet HE got mad about being waived and having his contract terminated... Maybe in a stronger room with better voices, his urge to fit in works in favor of prolonging his game. In Buffalo, he was right up with EKane as a poster boy for not being ready to play and trying to get by on his physique from when he was a teenager.