Specifically, the photo featured the actor wearing a shirt that says “Legion of Doom” on it, in the same font used for the Justice League font.
Could we see the Legion of Doom in Justice League? However unlikely it may seem, there’s some evidence that suggests this could be the case.
As innocuous as a Legion of Doom shirt may seem, nobody online appears to have seen this particular shirt before and, considering it has the exact same font as the Justice League logo, coupled with the fact that the guy wearing it, as far as we know, is playing Deathstroke in the DCEU, there’s enough circumstantial evidence to make us think that this could mean something more.
There’s almost no question, when Justice League arrives next month, we’re going to be in for some surprises.