Looking at last nights game and the starting formation, you can understand how Perisic would fit in, forget favourites for the time being, if Perisic started instead of Darmian (who played quite well). Tony and Ivan would give us natural width as wing backs and also the flexibility to change formation without making substitutions, Tony can drop back as a traditional RB, The left sided CB (Blind, who did'nt play well) drops to LB and we have a tradional back four with whatever formation in front of them 4-5-1, 4-2-3-1, 4-1-4-1, 4-3-2-1 etc