If he has fallen fowl of Benitez and it's because his attitude isn't right then being dropped is correct. Every player should be going out to perform a role for the team and not looking how the team can give them something as an individual. Perhaps Benitez is happy having a defence that is just concerned with defending and he doesn't want marauding wing backs which isn't great news for Lucas.
The problem is you need players like Digne to take you to that next level, to make something happen when everyone else has been marked out of the game.