Is it possible that this is our first look at Slade Wilson, AKA Deathstroke, in David Ayer's Suicide Squad? We haven't actually had any official confirmation that the character will even appear in the movie, but he's strongly rumoured to be who Jim Parrack (True Blood) will be playing.
Aside from the big-ass firearm, there's nothing in the pic to suggest that it's Deathstroke, but Ayer wouldn't have any reason to obscure the identity of one of the other Squad members considering we've already had a proper glimpse of 'em - be it officially or otherwise. Whoever it is in the image, he's clearly involved in a scene at a firing range.
Directed by David Ayer from his script, Suicide Squad also stars Will Smith (Deadshot), Joel Kinnaman (Rick Flag), Jared Leto (the Joker), Margot Robbie (Harley Quinn), Jai Courtney (Boomerang), Viola Davis (Amanda Waller), Cara Delevingne (Enchantress), Jessie Eisenberg (Lex Luthor), and Adewale Akinnuoye-Agbaje (Killer Croc), with Raymond Olubawale (King Shark), Jay Hernandez, Ike Barinholtz, Jim Parrack, Adam Beach, and Scott Eastwood. The film releases on August 5, 2016.