Cyborg has been confirmed for a small cameo in the film but Joaquim Phoenix is no longer attached to the film which blows the idea of the Joker returning to the silver screen but Jason Mamoa has been confirmed for a role. Speculation suggests that Jason will be playing Metallo because a former screen writer for the film was let go due to creative differences. In retaliation, the screen writer revealed plot details such as Metallo being Lex Luthor ' s muscle and second villain for the film