I think aesthetically assessing Sully is a mistake. He looks to have the body type that will always look plump.
That being said, it'll be interesting to see what happens with him, but from the way there has been a high priority on "high-character/work-ethic" type guys under CBS, I'm waging Sully doesn't have too much time left here. CBS seems to like the mold of guys like Smart, Bradley, Zeller, Crowder, JJ, and Johnson, and I'm not sure that you can put Sully in that character of guys.