Sorry, but I'm not getting into a "who sits between McGinn, Foegele, Wallmark and Martinook" debate in the middle of July.
Yes, Wallmark is the only center, and yes, Wallmark did well last season, and yes, Wallmark probably has more development to do. But somebody has to sit, and I doubt if they re-signed Martinook for two years to be the 13th forward, and as much as Roddy likes McGinn, he freakin' loves Foegele, so he's not sitting. And as long as McGinn is on the team, he's going to be tough to sit (a la Chad LaRose).
Like I said, I'd move somebody. Even Wallmark.