The overwhelming consensus on NSC is that we'll play a back three/five. Now you're saying we'll play a back four. My hunch -- well, it's more than a hunch, it's based on two season's worth of evidence and Swansman's input -- is that we'll play both. I also think you're reading too much into...
Pretty sure that's happened (in the second half) at home too. We had the Newcastle away game on while playing Monopoly the other day, and Solly moved to the right in that game when BDB came on, but it seemed as though we shifted to a back four with White at RB and Solly further up the pitch.
My contribution to the debate is that Potter values flexibility in players. This is because he changes formation within games and, while there are certain players who will play in precisely the same position and formation, there are others he will change their position/formation within a game.