I don't think Foster's move is permanent. First of all, Pelini said it's not. Second with Newell this year and the Davis twins next year, we are in good shape at DT for some time.
This is what bothers me with Pelini some times. If it's not permanent, and the intention is to get him back at guard - coupled with the likelyhood that he won't be playing any snaps at DT anyway, what's the point of moving him and taking away 1-2 weeks of education...perhaps his best chance to improve on the OL during the entire season? Moving kids in fall camp is a major setback, and this move seems like nothing more than having a body there so he can run a second defense.