Duncan, who passed away in September (12), had been due to reprise his role as mercenary Manute in the follow-up to the hit 2005 film.
Casting bosses working on Sin City: A Dame to Kill For have now decided to press on without him, giving the part to Haysbert, best known for his role as President David Palmer in Kiefer Sutherland's hit TV drama.
The film's co-directors Robert Rodriguez and Frank Miller say in a statement, ""Manute is a character that has been part of the heart of the Sin City tales, and the late Michael Clarke Duncan beautifully established that role onscreen. We could not tell the story of Sin City: A Dame to Kill For without Manute and are thrilled to welcome Dennis Haysbert to the cast.""
The follow-up, which stars Mickey Rourke, Jessica Alba and Rosario Dawson, is due for release next year (13).
The Green Mile star Duncan died from respiratory failure in hospital seven weeks after suffering a heart attack at his home.