Here's another beauty of that formation.
Playing 4-3-2-1 means that you have 3 midfielders in the starting XI and if Ranieri wants 2 players on every position, it means that we will need 6 midfielders.
Right now we have Sissoko, Poulsen, Marchisio, Tiago, Zanetti, Camoranesi, Marchionni...