Tretter is a boss center. Guards are paid more. Could still get a fat ass paycheck. But yeah, in the most selfish way, he should stay a center and Matthews should pin his ears back every play at the weakest OL and Spriggs should refuse to play guard too. But most of these guys are social by nature and want to help the team and don't want to split from their "pack" (no pun intended), so I think he'd probably move it asked to. And I respect that. I make sacrifices for the group in my life too.