My guess is that Sully has been doing more strength and a little less conditioning. Probably didn't even start conditioning training until a few weeks ago to let his ankle completely heal. I am a little disappointed, but I won't judge until training camp starts. I am happy he is getting stronger, but now he also has to get leaner. Still has another two and a half months or so until training camp, so there is still time for him to drop a good 20-30 pounds from where he is at now.
Also, cardio is the easiest to work on during the regular season. Lots of players use a bike during games, and before and after games to keep them in top shape (Humphrey's did this). There is no reason for Sully to not be working on reducing his size even during the season as well.
Though, while I can only reserve judgement for now, I will be p---ed if he shows up heavy after a full mostly healthy offseason to work on himself.