CAPTAIN MARVEL screenwriter John August takes time on his blog to reveal that the “Jake Gyllenhaal is Captain Marvel” thing is 100% not true:
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.
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.
But if you happen to bump into the internet, please tell him what I said.