For a show that doesn't include any pre-established comic characters, why would they use Luke Cage in the pilot episode? Chances are that this is a new character created for the show, possibly the villain in the pilot episode. But Cage is possible.

Cage would be a good supporting/occasional character to include if they are going to use established superheroes. But I don't think they are going to cast J August Richards in the role of Luke Cage. And they aren't going to cast him with the idea of recasting the character later.