I think in a general sense Sully did betray the Celtics. He was here four years, didn't seem to improve and was incapable (food disorder) or stubborn (arrogant) about getting into shape.
A little bit of this is the Celtics' fault. They were short on centers and told him he could expect minutes at the five spot.
If I am ever wrong, it is not on purpose. I like to go by memory and not fact check it every time.
Sully's first year was the last year of the slow Big Three era. His weight wasn't a problem so much when Doc, KG and Paul were playing old man basketball.
So here comes Brad Stevens who spoke of wanting to run the ball more or something about motion and passing, like the Spurs?
Something about motion offense.
Anyway, I thought Rondo was making a good effort to try the new system. I could see the kind of philosophy Stevens had by watching Rajon's attempt to do what he wanted.
Then came Rondo's matador defense and a Brink's truck on its way. He was traded and that was the big change I think getting Jae and then Isaiah later on.
Sully no longer fit in. I would see someone make a great defensive play only to watch slow Sully have no chance of finishing off a team steal.
Sully couldn't block shots. Olynyk was new to the center position and maybe that too set fate for Sully's departure.
Sullinger betrayed himself more than us or the team, but I think there is some truth to what Rollie says.
Sometimes people get divorced. Sometimes we lose contact with certain friends.
Sully as constituted is one of the last players I was worried about losing. He is an overweight power forward who can use his bulk to push the Dwight Howards out of the paint.
Sully is what he is unless he tackles his weight problem. He is basically a Big Baby Davis, very similar with a few differences.
Speaking of Big Baby, I like this article from April.
http://gioandjones.radio.cbssports.com/2016/04/25/glen-davis-explains-why-he-didnt-play-this-season/He was at 335 pounds and it says his playing weight is 315.

Someone should send the link to Sully and tell him it's now or never to get his act together or Big Baby is his future.
I agree with Shak Not Shaq that maybe Sullinger is living the good life and couldn't care less. Perhaps we care more about Sully's NBA career than he does.
It reminds me of some things I saw mentioned on James Young. I am not sure, but he seems to be more into the NBA lifestyle than working hard to make it. Or James Young is simply in over his head.
Sullinger made it. He can probably stay in the league a long time as long as there are teams who don't mind playing slow. It doesn't mean he will play a lot or end up any better than Glen Davis.
Those two guys are what Rollie was talking about with skilled bulk. Yabusele might show the third Danny attempt as the charm. He doesn't seem to have any food issues. Pierce had food issues. He is the role model for NBA players to overcome it.
They have orientations now for rookies, I think, where they warn them of the money and how if they are not careful, they could throw it all away. Maybe they should spend a little time on food disorders also.
I will not feel betrayed if Sully turns it around. I will be happy for him that he finally figured it out. I'd be more afraid of losing an Olynyk, Smart, Bradley or Brown and having it backfire than Sullinger. He's good, but not great. I don't think he can ever be great. I would put Sully at the level of Evan Turner with Turner the better player because he is in good shape.
This isn't golf. You can't weigh 300 pounds and walk from hole to hole. Basketball is a fast game.