Servais killed it at RT in the spring. While he may be the best option at Tackle, have to think he's also the best Center.
Game experience is a factor, and we have no meaningful tackle snaps.
If Clark was injured, I don't recall him regaining a 2T spot, but we all know the depth chart isnt always quite right.
Without a grad transfer, my guess would be :
LT Servais
LG D Davis
C Heckel
RG Adams
RT ?
With a grad, Servais back to C, or RT. Heckel to LG, with D.Davis spelling the G position like Heckel did this year. Again, questions at Tackle, but more depth, and a little more comfortable.