Knowing Zaccheroni's past, against Lazio there is a very good chance we will see something similar to one of these formations
3-4-3
Buffon
Legro Cannavaro Chiellini
Salihamdzic Sissoko Melo Grosso
Diego Amauri Del Piero
OR
3-5-2
Buffon
Legro Cannavaro Chiellini
Salihamdzic Sissoko Melo Grosso
Diego
Amauri Del Piero
With the possibilities of candreva playing on the right and De Cegli playing in the left, instead of Salihamdzic and grosso respectively.
There is also a chance of seeing a fullback replacing one of the back three: e.g. Grygera playing in Legro's position or Grosso on Chiellini's position.
The great thing about the 3-4-3 (or 3-5-2-) formation is that it takes away our greatest weakness FULLBACKs. Instead you have two side midfielders with defensive duties.