While Baron Cohen left the film due to his busy schedule promoting "The Dictator", Russell's reason of departure is still unclear, reported Ace Showbiz.
Baron Cohen announced his departure in a recent radio interview.
"That was going to be a cameo, but I had to drop out because of 'The Dictator' press tour," he said.
The British funnyman was originally expected to star as Scotty Harmony, a gambler who buys Django's wife as a female companion.
As for Russell, he was originally tapped to replace Costner in the movie. He was expected to tackle the part of antagonistic Ace Woody. The character is described as a sadistic trainer of male fighting slaves and of female prostitutes.
The remaining cast members of "Django Unchained" include Jamie Foxx, Kerry Washington, Leonardo DiCaprio, Christoph Waltz, Samuel L Jackson and RZA.
Set in 1800s, "Django Unchained" follows a freed slave who, under the tutelage of a German bounty hunter King Schultz, becomes a bad bounty hunter himself. After assisting Schultz in taking down some bad guys for profit, he tracks down his slave wife and liberates her from an evil plantation owner.
The film will hit the theatres on December 25.