To do well next season we are going to have to keep more than a handful of clean sheets and be able to defend a one goal lead. We are also going to need to be dangerous coming out of defence - Lochhead, and whoever we sign at right back, need to be able to go forward whenever the opportunity arises. I can't see how we can create this sort of defensive capability with three at the back. I think Ricki has already said, subject to finding a right back, he wants to play four at the back.
Assuming we get Mulligan, or another right back, and Porter, or another striker, the interesting challenge becomes who plays where in the midfield.