For better or worse, the DCEU is here to stay. What form that takes is anyone's guess, as it seems to be very reactionary to the fans. Sentiments toward Man of Steel informed Batman v Superman, and reactions to Dawn of Justice supposedly formed the hodgepodge that was Suicide Squad. And if the trailer for Justice League is any indication, that film will also suffer the same fate. So when Jeffrey Dean Morgan says "There's a chance I could be Batman," the guy probably means it.
Speaking with Cinemablend, the Watchmen and Walking Dead actor alluded to a conversation he had with Zack Snyder about playing a version of Batman, namely an alternate universe Batman where Thomas Wayne never dies and ends up donning the cowl himself.
"I have not had any big discussions with him about [Flashpoint], but I remember when we were in Australia doing Watchmen press, and I was having dinner with Zack or whatever. And he was like, 'My dream is to do the Frank Miller Batman.' And he goes, 'You would be an awesome Batman.' The darker version."
"Maybe when he cast me that was kind of the goal. Hopefully DC can figure this all out, and in a few years I can come back and do a Flashpoint Batman! I would love it. That would be great."