Robin??????

While watching Avengers I saw the trailer for The Dark Knight Rises and I came up with a theory involving the character played by Joseph Gordon-Levitt. What is Levit is actually playing a retired Robin. I know Nolan said he wouldn't have Robin in his franchise, but Dark Knight Rises takes place 8 years after The Dark Knight so it is conceivable that Batman had a Robin in that time would either left or Batman forced out. So it wouldn't be Robin per say.There is a theory that Bruce Wayne dies at the end of Dark Knight Rises and Levitt's character becomes the new Batman so it would kind of fit if Levit used to be Robin.