Well it all depends on how the players will move around the pitch, what formation we line up does not matter. Allegri can say we play 6-4-0 if he wants and I wouldn't care, at all. Actually, I'd prefer that he did. In this year's coming CL final I'd like him to field this team.
Szczesny;
Dybala, Chiellini, CR7, Pjanic, Costa, Matudi;
Can, Sandro, De Sciglio, Benatia;
On the field that would mean that Sandro will take care of the left flank as a LWB.
Chiellini and Benatia will defend the castle.
De Sciglio will help defend the castle and balance the team, although sometimes moving forward to increase width.
Pjanic will be our regista per usual, hopefully making the team tick as he even on bad days manages.
Matuidi will chase the ball and look for fast recoveries high up the pitch, mainly on the left side of the pitch. He will also make a lot of forward runs. For good and for bad, these are important runs to open up spaces. Sadly, he will also be given a lot of opportunities that he will not be able to take advantage of because, well, he is Matuidi. In defense he will track back to help Pjanic.
Emre Can will surge forward to push the line along with Matuidi but he will likely have a balancing role similar to Khedira. However, he is more aggressive so I suspect he will look for ball recoveries higher up on the pitch. We will then be vulnerable to counters, but if De Sciglio has the hand brake in, we might be less susceptible to sudden counters. Nevertheless, I believe he will protect Pjanic more than Matuidi does and offer a more creative outlet than Khedira.
CR7 will start from the left to come from behind centrally, or sometimes lead the line. In a sense he roams around but he will roam a lot less than Dybala. Dybala can start from a central position and then drop deeper. Costa will roam to some extent to but mainly stay on the right side since we have no one on that side.
What I am worried might happen with these players on the pitch... which is essentially the same as last year but CR7 instead of Pipita and Can instead of Khedira, is that I think the players preferred roles and movements might cause some issues. CR7 is a striker but is IMO better when he has someone in front of him rather than Dybala dropping even deeper (which I think he will) than Benzema. No one can find open spaces as CR7 and he is IMO the smartest player in the world in that regard. Some of those spaces may be opened by e.g. Matuidi and by Dybala dropping down. But I also think there is more to gain from his abilities if e.g. Pipita or Mario plays in the front. That means I would take out Costa, and we'll have absolutely no width on the right end, and I doubt Dybala will track back to help De Sciglio. Therefore, I would instead take out Matuidi and ask Can to take a deeper position to help Pjanic. Since that would core would be more stable then, I would try playing Cancelo to the right back instead of De Sceglio.
Hence, if you want a "fixed" formation;
Szczesny;
Cancelo, Benatia, Chiellini, Sandro;
Costa, Can, Pjanic;
Dybala, CR7;
Pipita
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