Sylvester and Sage Stallone are apparently the duo negotiating the deal (both plan to star in the film, playing father and son). The only casting rumor thats surfaced is Vin Diesel playing the new opponent. I assume he'd be playing some kind of new hot shot, because the script reeportedly revolves around Balboa's big comeback and a new hot-shot that he has to bring back down to earth".
Dark Horizons
Please. No.