With Robert Pattinson's Justice League, the plan was to have his Batman star in a solo-film that was initially being directed and written by Affleck.
But as things began to unravel about the planning of DC films behind the scenes, Pattinson was officially cast as the new Batman, confirming that the film would take place during Bruce's early days as a crime-fighter. Affleck used this as a chance to bid farewell to the franchise to focus on other projects that spoke more to him.
In a recent interview with DeWayne Hamby to promote The Way Back, Affleck was asked if the door was truly closed forever on him returning to reprise his Batman. In the video, posted on YouTube, Affleck politely reaffirmed that his time as the DC icon is over. While appreciative of the time he had playing the famous superhero, Affleck states that although he "had an opportunity to write and direct and kind of star in a standalone Batman [film]," it occurred around the same time he "kind of lost interest in those stories." Affleck added that he'd happily go and see Pattinson's new iteration of the hero.
While the interviewer jokingly suggests the possibility of Affleck returning to the role in an adaptation of The Dark Knight Returns, Affleck seemed partially interested in the idea. But that would involve telling the story of an incredibly old Dark Knight, which probably couldn't happen until Affleck ages another ten years. As much hope, and hype there is from fans for Affleck's return, it's becoming more apparent every day that Warner Bros. only has eyes for Pattinson's Batman, for now.
Currently, The Batman's place in the DCEU is a mystery. Shazam continuing, will they recast another Batman to appear in ing roles in continuity-linked DCEU films? Only time will tell, but as far as Ben Affleck goes: his time as Batman is officially done.
Source: DeWayne Hamby via YouTube