Black Adam has now been confirmed moments ago to be playable via the Injustice Facebook page.
I am very interested to see how they make him play different than Shazam (Captain Marvel) with the both having similar powers. In the pictures below you can see the way he looked in the Luthor story trailer, his action figure, and the picture they revealed today. If a trailer is released soon we will update this post so you can see his gameplay.
Gameplay from Pax East