Whoever expected Sullinger to be 240 pounds next season needed to put their expectations in check anyway. He stated that he's targeting 260 for the start of training camp. If he's been at 280+ for the past year, 260 is an excellent weight to target because it would make for a gradual weight loss over the next 3-4 months.
He might never be 240 and he doesn't need to be... He needs to be in the condition that allows him to be the fastest version of himself, maintain his strength, health, and his stamina is at its peak.