True, it comes down to whether or not they want to take the potentially best RW they have or stay true to those who helped out in qualification.
That said, there's a whole bunch of players in qualification who were always on the bench and didn't do all that much to help the team to get to the World Cup, and a lot of them will still get a place in the squad, so I don't see why Navas can't, especially if he's in great form come the end of the season.