So, this is a shocker. It seems that Ben Affleck might not return to the Batman role after JUSTICE LEAGUE, not even Matt Reeves' upcoming solo BATMAN film. Which is a shame if true, as he was one of the only good parts of BATMAN V SUPERMAN, and seems to be doing more good work in the upcoming JUSTICE LEAGUE.
Now, of course, this is all only rumors for now. However, sources close to The Hollywood Reporter seem to think there's some merit to it. If the rumor is true, they're claiming "that the studio is working on plans to usher out Affleck’s Batman — gracefully, addressing the change in some shape or form in one of the upcoming DC films." So it seems it won't be a simple recasting, with a new Bruce Wayne turning to Wonder Woman saying "it's me, I'm here, deal with it."
As bad as this can be for the DCEU, it also isn't unprecedented. When it seemed Edward Norton was going to be difficult to work with going forward, he was replaced by Mark Ruffalo in THE AVENGERS, and fans have seemed to agree that was a fair trade. So even if Affleck is replaced, it wouldn't be a new occurrence in a cinematic universe, nor would it necessarily be unwelcome (no matter how good a Batman and Bruce Wayne he is). Other possibilities brandied about are him being replaced by Dick Grayson's Nightwing or a proto Terry McGinnis from BATMAN BEYOND, though those ideas are – sorry – stupid. I hope they don't go that route, personally.
Meanwhile, you can see Ben Affleck for sure as Batman in JUSTICE LEAGUE November 17th.