It needs to be made painfully clear that lack of depth at the fullback position is going to be a problem this year. While there has been discussion about moving Mattia DeSciglio to right fullback and using Armero as the left fullback, the fact that this conversation is happening shows how far from good defense this team and fan base has come. There was a point where Abate and DeSciglio were considered the future of the Azzurri back line. There is no reason why this still can't help and why Filippo Inzaghi can't put his faith in that duo. A 4-3-3 should allow for more width and actually help those guys get into positions to make smart plays and keep the balance. For me there is not debate on those two, if one goes down or needs a break we are screwed, that much is clear.
As for center back, it's a hodgepodge of mediocrity. Alex, surplus to need at PSG. Phillipe Mexes, inconsistent garbage who Inzaghi asked be sold but nobody wants him. Christian Zapata, never regained his old Seria A form. Michelangelo Albertazzi, capable but lacking in experience. Adil Rami, thanks to the lack of good center backs this guy was like the second coming, the reality is he is average at best. So where do we go from here? Frankly I say start Alex and Albertazzi! Now here me out.
The reality is this team is going to be a work in progress, so there is no reason why solid young players like Albertazzi can't be groomed early and often. While I have never been a big proponent of playing youth for the sake of playing youth but if you take the body of work from last season, one could argue that in his 31 appearances for Hellas Verona last year he was a solid starter and played more consistently then the guys on Milan's list. Pair him with an older guy like Alex and you can play a decent mix of youth and experience and deploy a solid pressure cover pair.
Mexes should invariably be sold and then Bonera and Zaccardo can cover the fullback spots while Rami and Zapata press for time at CB. In my opinion the reality of this season is relatively simple. If Inzaghi is given time and patience and not forced to win games his team isn't capable of a grooming can start. If he needs to win now with a subpar team than the problems will continue, and the defense won't be of any help.