Sean Smith will be a Top 20 pick after the combine
I dont think depth at guard is the issue. Your backup guards are not going to be as good as your starters. Thats to be expected. We made the playoffs with Ike and Alleman starting at guard. I am confident with them as the backups.
Jason Brown would be a terrific addition at center, though. That extra 20 pounds that he has on Samson will come in handy against Wilfork and Jenkins.