Multiple reports are saying that Rogue One star Riz Ahmed is currently in talks to join Sony's Venom film, but it's unclear which role he will be playing since there are multiple conflicting reports on who exactly he'll play in the film. Carnage is expected to be the main villain in the film, so Ahmed might be in talks to play him but we still don't know for sure.
We've heard rumors that Ahmed will play Carnage, but the Tracking Board is saying that the production team is "torn as to whether he’ll ultimately play that character or a different one."
In addition to those reports, Variety reporter Justin Kroll wrote on Twitter that Mathias Schoenarts (The Danish Girl), Pedro Pascal (Game of Thrones), and Matt Smith (Doctor Who) were also being considered for the role that Ahmed is in talks for.
Insiders say Ahmed not playing Carnage though sources say he was up for it before script changes.— Borys Kit (@Borys_Kit) August 10, 2017
As of right now, the role Ahmed is being considered for hasn't been confirmed. It might be Carnage and I think he can pull the character off but we still have no official confirmation about that.
Venom will be released in theaters on October 5, 2018.