I think you know that a lot of strong team even use guards in Sf position and often they have less Rb then Eidinas.
If team would use a guard on SF position Eidenas would be destroyed with his low OD. By the way, what would be an advantage from his high ID vs guard on SF?:) As I said, Gello know what I require and I think Eidenas will be strong member of Lithuania NT soon. Increasing OD will help him for sure.