The 'Guns, Girls, and Gambling' actor is the latest addition to the cast of the currently untitled movie, which is based on the French comic series 'Bullet to the Head', in which Variety reports he will play a "local handler who acts as a middle man".
Also joining the movie - in which Sylvester plays a New Orleans hitman who joins forces with a Gotham policeman (Sung Kang) after both their partners are killed - is 'Lost' actor Adewale Akinnuoye-Agbaje and 'Lights Out' star Holt McCallany.
Adewale is to play the main villain, an attorney who tries to cover up his scam to exploit poor victims of Hurricane Katrina, while Holt is a 'dirty' cop partnered with Sung's character.
Already cast in the film are Jason Momoa as villain Keegan and Sarah Shahi as Sylvester's character's daughter.
The script has been adapted from Matz and Colin Wilson's graphic novel by Alessandro Camon, while Joel Silver and Andrew Rona are among the producers on behalf of Dark Castle.