I don't particularly like playing either Ogbonna or Chiellini as a dedicated left back.
Peluso can probably do it better - at least in terms of offering something going forward - and both those centre backs are wasted there in my opinion. Peluso's main problem when played at LCB has been offering attackers too much space on the outside, as he doesn't look comfortable with the added duties toward the middle. The extra space behind him/to his right seems to make him indecisive. When he has the touchline to help him he's a good enough defender.
De Cegile is bollocks and we all know it, so we need another left back that's solid at the back and decent enough going forward.
Let's get Criscito.
A 4-man backline of Lichtsteiner (Caceres), Barzagli (Bonucci), Chiellini (Ogbonna) and Criscito (Peluso) looks solid enough for me.
Sell Isla, get Martin healthy, buy a left back and a 4-man back line is good to go.