The “Peter Brand” character was originally going to be named Paul DePodesta, who was Billy Beane's assistant at the time (he later served as Dodgers' GM and was employed by the Mets at the time of the film's release). Demetri Martin
was originally cast for this role. However, DePodesta, who visited the set, objected to his portrayal as a pure stats nerd, and so the character name was changed. By the time this was done, Jonah Hill
had been cast in the role.