The rumor of Gyllenhaal being considered for the role came from the New York Daily News and was recently debunked on John August's blog.
"But the thing is, he's not considering," August wrote. "I can pretty much assure you he's never heard of the project. And we've never discussed him. We've never seriously discussed anyone."
August added: "After several months of meetings, casting has come up exactly zero times. There's no casting list. If there were a list, Gyllenhaal's name would probably be on it, but trust me: There is no list. There's no start date, no release date, no movie whatsoever. There's just a script to be written. Which I should probably get back to." Shazam! is based on the DC Comics series.