6 weeks if you want to be safe.
And I have to say, the way players from Mexico, Chile, and Colombia went after Neymar was reminiscent of Pele being fouled off at the 1966 WC. And we all recall what happened then, don't we?
Even Messi hasn't been targeted anywhere near as horribly as Neymar was. In many ways, Fred's theatrical fall to claim a penalty in the first game has worked against Brazil: the coaches of opposing teams have pressured the referees not to allow Brazil to claim such "easy" fouls, and then taken advantage of that to go after Neymar.