Also, he's not really fat. He could have a long career at this weight. The concern (other than the back surgery) is his pulling a Hot Plate/Oliver Miller/Tractor Trailer move and gain weight. It's hard to call it irresponsible or unprofessional when he spent the offseason (when he would have been working on his strength/conditioning) recovering from back surgery. I'd see it as more of an issue next year if he looks the same.
To me, the shape he's currently in is worrisome on its own accord. He's clearly carrying too much for his frame, whether you'd call him fat or not. I mean, it's good that he doesn't look like Michael Sweetney, but is this really the measuring stick here?
I appreciate the fact that he was recovering from back surgery -- but I don't buy the excuse, since I've seen other athletes go through more complicated procedures, and not come back looking like Chubby Checker. Rondo, Gronk, and even Al Jefferson come to mind right away, I'm sure there are more.
The thing is, he was in great shape for the draft and early on in his rookie year, then never bothered to maintain that. I don't expect everyone to work out like Kevin Garnett and Kenrick Perkins, but I can't pin any sort of long-run hopes on an undersized, overweight forward with chronic back issues -- regardless of the talent. In my book, he's in the "all we can get is a bonus" column so far.