While fans might've had some hope for The Batman to be part of the current DC Extended Universe, recent casting news has now severely dented its chances of fitting into the established canon. The DCEU began in 2013 with Man of Steel and has since produced six more films as part of its interconnected universe – but not all of these have been well received by critics and audiences, prompting Warner to reboot some of them.
The Batman is already a major departure from the DCEU, with Robert Pattinson replacing Ben Affleck as the Dark Knight, after years of speculation as to whether Affleck would stay in the cape-and-cowl or not, and Matt Reeves writing and directing. Although a younger Batman doesn't completely rule out The Batman from being part of the DCEU, it does seem more likely, and the general word is that this will standalone from the rest of the universe, which has now been more or less confirmed.
There have been a couple of pieces of The Batman casting news recently, but most pertinent to its place in canon is that Jeffrey Wright is in talks to play Commissioner Jim Gordon, which is an exciting idea, except that it contradicts the DCEU canon. Commissioner Gordon appeared in Justice League and was played by J.K Simmons, so by having a different actor playing the role, The Batman would definitely be left out of canon, unless they can find a very creative and effective way to justify this change (and the rest), but that seems very unlikely.
Sure, it wouldn’t be the first nor the last character in a franchise to go through an actor replacement, but Commissioner Gordon could have linked the DCEU with The Batman. Unlike with Pattinson, there's no way of making this casting line up with canon by saying it's a prequel to the present-day DCEU stories. Although Reeves has previously said that The Batman will only have small connections to the greater DC Universe, and will definitely not be an origin story (after all, it has been told enough times already), many were hoping that it would still somehow connect to the previous films in the DCEU, but those hopes now seem truly dashed.
DC has a big opportunity with The Batman (and the rest of the upcoming films, but this one is the biggest for now) to successfully reboot its universe and make it one that will stand by itself, without the constant comparisons with the Marvel Cinematic Universe. The Batman can’t be part of the current canon anymore, but it can build its own and be the lead for the rest of the films in the DCEU.
