That's Kalas case is mainly because he is injured at the start of the season. And after that he is struggle to make it, also because the team are getting solid by the time he is fully fit. About Zouma, who knows though maybe Jose could do 'Varane' to him. We will see how he perform, and how Jose will use him in the pre season. But I'm also understand some of your point though that Zouma somehow not ready yet, that's why I wish for Omeruo, I think he is 'experienced' enough.
Heard that he could play really well too in RB position. If I could wish, hopefully Omeruo will be included in squad too. Yes both are very young, but they are quality and could learn from senior players ongoing. They won't play as a regular starter for a team like Chelsea anyway, but could be a useful backup. Then we don't need to sign a high profile CB. Could 'save' the money for someone like Pogba. A new LB, Ake - Cahill, Terry, Ivan, Omeruo - Azpi and Zouma could do the job. 2 players every position, with Ivan, Azpi and Zouma could play in more than one position, could well cope any injury or suspensions. Also why I wish for Omeruo because Kalas has been loaned out.
What I'm talking about is the Argentina game. He is totally missing from the game. He could do it better in my opinion. I don't have any complaint about Hazard in the group phase as well as against USA. If only he could play like that against Argentina. I don't think tiredness is the cause. If that is the cause he will play shit from the first group match.
Back injury http://www.dailymail.co.uk/sport/worldcup2014/article-2682231/Willian-forced-Brazil-training-session-injury-ahead-World-Cup-semi-final-Germany.html But it seems it is not that serious, media hype?
Probably early to mid August. Depends on how they went far in the tournament, I think. We will see Spanish and English players joined first, and then Brazilians and Schurrle would be the latter.