The latest rumor is that if Ben Affleck is out, Jake Gyllenhaal is in as Batman.
Revenge of the Fans claims that Warner Bros. is "sour on Ben Affleck" regarding a return to Batman, and if Ben Affleck bails, then "Jake is in."
(It's actually my guess that the decision regarding Ben Affleck returning as Batman has already been made, and that it has been known for a while.)
Now the site also contradicts an earlier rumor and offers that the Matt Reeves Batman movie is indeed set within the DC universe, which is what Reeves tweeted a while back as well.
It's further said that Matt Reeves' Batman movie "is DC proper," just that the Matt Reeves Batman movie is its own story.
The earlier rumor also claims that Ben Affleck may be a part of Suicide Squad 2 and/or Flashpoint.
Regarding Jake Gyllenhaal as Batman, the actor was once up to play Batman for Christopher Nolan, but the part went to Christian Bale.
A Hollywood producer is said to have confirmed Jake Gyllenhaal is wanted as the new Batman, and another rumor stated that Jake Gyllenhaal has met with director Matt Reeves, but Jake Gyllenhaal hasn't locked in the role (as of November 2017), and that Reeves has met with other actors.