In an interview with Collider, Dwayne "The Rock" Johnson made mention that he may be playing a DC character in an upcoming DC film. Johnson is a fan of comics, in general, having used #JohnStewart hashtag on his Twitter page because he loves the character. During this interview, Johnson said this about the character he may eventually be playing:
The first quality we were looking for was that he had to be extremely complex and have a lot going on. What that does for me as an actor and the studio is it gives us space that we can explore; his complexities. The other quality was that he had to — the character we were looking for had to be well-known but never brought to life. Then what that does again as an actor, it gives me a little bit of space, and we talked about personality. It just gives me a chance to put an imprint into his personality, with the set of tools that I could bring to the table and put a very unique twist on his personality, but still pay homage to who he is. The third thing — and most important — is he had to be a badass mother***ker, okay, and on a Superman level of power, where could throw down. In those three qualities, I’m happy we’ve found that character. Right now, we’re out to a lot of writers.
To break it all down, he may be playing a complex character, who is well-known but never brought the life, who is also on Superman's power level. This leads many to believe Johnson could be playing either Lobo or Black Adam. However, Green Lantern John Stewart isn't too far off from that. Sure, he's not exactly on Superman's power-level, but he's not too far off.
What sounds most probable, out of the three, is Black Adam. Johnson really has the look for the character, and who knows if DC would want to dabble back into the Green Lantern mythos after the last film, unless the character was involved in a Justice League film. Black Adam is a much more complex character who is easily on Superman's level. He's also one of the coolest and toughest villains in the DCU. However, this is just the Comic Vine perspective.
Who do you think Dwayne Johnson will play in an upcoming film? More news on this as it develops. Keep an eye out for more announcements about this during the summer.