Certainly looks that way. He could play either Shazam or Black Adam as both have to “say the word” as Johnson mentions in his teaser for the upcoming big reveal as well as him having the right look for both Adam and the Big Cheese.
Taken from superherohype.com:
Back in March, fan favorite actor Dwayne Johnson laid out that he and Warner Bros. had been in discussions for a long time about what DC Comics character he could play on the big screen. At the time, it seemed like it could be Lobo or potentially the villain Black Adam, but now in an interview with Total Film, Johnson not only confirms that he’ll be playing a character but appears to say he’s playing Shazam.
“I will say this. There’s a character out there that we’re going to announce very soon that I’m going to play, and I’ll just say this: This character has the power of Superman, he can throw down. Just say the word. That’s all I’m going to say.”
If you recall back to the slate of DC Comics titles that popped up last month, a “Shazam!” solo film was said to follow the upcoming Batman v Superman: Dawn of Justice for a July 2016 release date. Check back here on Saturday for our live blog from the Warner Bros. panel at the San Diego Comic-Con where they just might be revealing all these details.