Dude looks substantially bigger than last year. I see that as a good thing if he maintained his speed. Not sure what it says about his off season activities, but he is a pro athlete lvl physical specimen.
I remember back in the day it was kind of a rule of thumb that a draftee fresh out of college could gain, on average, 10-15 pounds in the pro game without hurting his game. Many colleges don't have the kind of pro nutrition and workout coaching that the pros do. It would vary by position, of course.
He was claiming to be around 255 when this picture was taken, but I'd expect that number to come down a tad between now and when he makes his season debut, esp. if he's going to be a Sam LB.