DC Comics president Geoff Jahns has himself announced that Joe Manganiello will indeed appear in Ben Affleck’s solo Batman film as the villainous Deathstroke. This comes after Affleck tweeted a short teaser of what looks like behind-the-scenes footage of Justice League, the footage showcases Deathstroke in full costume. This sparked many rumours, suggesting he will either appear in Justice League or Affleck’s Batman film. It seems likely it will be both.
Manganiello was last seen in Magic Mike XXL. He has been tipped for the role of Deathstroke for a while now, with rumours he would be cast in Suicide Squad. Jahns denied whether or not the character will be in Justice League.
— Ben Affleck (@BenAffleck) August 29, 2016
While Justice League is set for November 2017, Affleck’s solo Batman film could be seen as early as 2018, depending on development.