I can't envision a scenario in which Kampman is back.
Kevin Seifert of ESPN's NFC North blog says Kampman "seems unlikely to return" and "it's time for the Packers to begin a succession plan at both [left tackle and right tackle]" due to the age and unrestricted free agency of LT Chad Clifton and RT Mark Tauscher. They needed a succession plan about two seasons ago. T.J. Lang is good, but I'd rather see him replace Daryn Colledge at left guard. Hopefully both Clifton and Tauscher return for another season, and GM Ted Thompson can try and find another good young tackle or two in the draft.
Seifert also said that unrestricted free agent Ryan Pickett "could be phased out by B.J. Raji." I like Raji, but Pickett outplayed him last season, and the middle of the d-line would take a step back if Pickett leaves.