Xabi Alonso is using a 4-player defense line for now unlike his preferences at Leverkusen. It was like that in his first two games in the FIFA Club World Cup at least. I think this is the best choice because they would have rotational problems for CBs otherwise.
In case of injuries I mean. Anyways, it was nice to see Arda Guler as a starter too. Xabi Alonso cares about him way higher than Ancelotti. Unlike him, he wants to have Arda adapted to midfield. To play in Modric's role maybe. Let's see whether it works...