EW claims the Moneyball director has cast Carell as the lead in his new film, about the schizophrenic murderer John du Pont.
Foxcatcher retells du Pont's 1996 murder of Olympic wrestler David Schultz, despite police never discovering the multimillionaire's motive for the crime.
Miller's frequent collaborator Dan Futterman, who also wrote the Capote screenplay, will pen the film's script alongside Eric Max Frye.
Production on Foxcatcher is expected to begin in March 2012.
Watch Steve Carell in the trailer for Crazy, Stupid, Love below:
> Crazy, Stupid, Love - review