At the start of the second half on Sunday Allegri made one of the most proactive subs of his Milan tenure. He finally recognized the inability of Urby as a CAM, a half too late mind you, and subbed off Antonini moving the ineffective Dutchman to LB and bringing El Shaarawi into the hole behind the strikers. The thing is El Shaarawi didn't really slot into the hole, nor did he function as a true CAM, none of the strikers did. Suddenly the time tested 4-3-1-2 looked a bit like a 4-3-3, but not the Leo version that gave many of us nightmares, but a hybrid that proved rather effective; scoring three goals in forty-five minutes.
The traditional deployment of a 4-3-3 calls for a center forward and two wing forwards, under Leo Milan operated this way with Ronaldinho, Borrielo and Pato. Allegri, like anyone else with two eyes, sees the lack of balance in such a formation and deploys the strikers in a much more compact triangle calling on width from his fullbacks, while still shielding the midfield to some extent. This deployment doesn't unbalance the formation in the midfield, but shields it, simply because of the amount of player traffic in front of the opposing central defenders and opposing defensive midfielder. While none of the strikers may actively defend, their mere presence in that part of the pitch makes it difficult for opponents to move the ball into the midfield. It is also a challenge for opponents to mark the strikers, which is the true beauty of this deployment.
While the formation lacks a true CAM, one of the strikers could drop into the role and cause the opponents defense to track the run, creating space for teammates. On Sunday against Novara, it was both exciting and fluid with the interchange between Robinho, Zlatan, and El Shaarawi almost seamless. It would appear these three had played together for years. Rotating, playing short combinations, and causing defenders fits as they were almost entirely un-markable for a 20 minute stretch. How can an opposing defense cope with marking three players in an area patrolled by two center-backs? Do they drop in a DM? Pinch in a fullback? All the while creating space for the added threats of Abate, Urby, and Nocerino!? This dynamic movement and attack when clicking can score goals at will, and strikers of the one dimensional variety all the easier to sell. Case in point, Allegri used and can use this deployment when Cassano is healthy and while it is a strong attacking formation, and that provides attacking entertainment. It is important to note that it may not be the best option against teams who can and will attack.
The deployment of Prince in the hole makes more sense against stronger opposition, adding more grit and balance, but also giving Milan/Allegri the flexibility to deploy a passing player in the midfield. Like all formations there are matches and situations where they can be tweaked and evolved and Allegri has found a good mix of work rate and industry in the absence of other strikers. Should he roll this out against Arsenal in February or Juve in a few weeks? Probably not, but depending on the team around them and their form at the time you could at least make case to see the hybrid 4-3-1-2/4-3-3 make a cameo.