The movie will focus on the Dark Knight and is reportedly planned under the working title 'The Batman' though Warner Bros has made no official announcement regarding it.
Affleck will return as Batman for a film due in 2019, Ace Showbiz reported qouting Latino Review.
The film joins a series of rumored DC projects that include 'Shazam!', 'Sandman', 'Justice League', 'Wonder Woman' and 'The Flash'.
The only officially-announced project so far is 'Batman v Superman: Dawn of Justice' which is scheduled for May 6, 2016.
Henry Cavill and Amy Adams are returning as Clark Kent and Lois Lane respectively. Gal Gadot is cast as Wonder Woman, and Jason Momoa is expected to play Aquaman.