Alec Ogletree is moving to ILB from safety, Bean Anderson is moving over to the offensive line, and Cordy Glenn is moving from OG to OT. On the offensive line it means that one of two things, either the coaches like the next guy up better at guard (Possibly Dallas Lee, or maybe Anderson that is being moved over from the DL) or that they value tackle more than guard and figure they can piece together the guard spot opposite Gates.
On defense it possibly means that Grantham trusts that between Jenkins and Geathers they don't need any more depth besides the occasion of moving Tyson over for pass rush situations (i.e. 3rd and longs). As for linebacker it helps give depth and higher top end talent at the same time. Ogletree is not changing positions to be a backup so expect him and Robinson to start in the middle and Jones and Washington to start on the outside. It gives a possible 3 man rotation at inside and outside LB when you throw in Drew and Samuel as the top backups. Jakar Hamilton will likely get a strong look after having a year to adjust to division 1 football from the junior college ranks and being in his second year in the system. Deas should provide him with strong competition and if neither of these lock down the starting position in spring I expect incoming freshman Corey Moore to have a shot because of his speed and coverage skills.
Big picture I believe that Ogeltree at LB gives his a lot more options at defending the spread. He can stay in the base 3-4 more often against the spread/3 wr sets. With a guy like Moore and Hamilton, who played a game last year at CB, that can handle covering some of the bigger recievers in the league and Ogletree being able to slide back to safety, Grantham has the option of leaving the same players on the field and disguising if he is in the nickel or staying in a 3-4.