In an interview with Total Film, Dwayne "The Rock" Johnson admitted that he has been in discussions for several years with Warner Bros. to play a DC Comics superhero.  Johnson talks about the difficulty in finding the right character to play, one that fits his onscreen personality, and he definitely rules out playing the John Stewart Green Lantern.

The Rock is coy about the role he is going to play, but he does drop some hints, noting that the character has "the power of Superman," and then says "just say the word," which sounds like a clear reference to Shazam (DC’s Captain Marvel, a character created by C.C. Beck in 1939 and acquired by DC thanks to lawsuit claiming that the character was just a rip-off of Superman, uses the word "Shazam" to transform from Billy Batson to the superpowered Captain Marvel).   
 
Having the Rock portray the lantern-jawed Shazam would make sense, especially if the Justice League movie is based on Geoff Johns’ "New 52" Justice League run during which Johns revived the DC version of Captain Marvel and added him to the Justice League team.  Henry Cavill is expected to play Superman in the Justice League movie with Ben Affleck as Batman and Jason Momoa as Aquaman (see "Jason Momoa Confirmed as Aquaman").  The Justice League movie is currently slated for release in May of 2017 (see "Warners' DC Film Schedule").