"[Affleck's] got a busy schedule,” producer Charles Roven told TOTAL FILM (via COMICBOOK.COM). “He’s about to start a movie now [LIVE BY NIGHT]. And he’s also got obligations to be in the JUSTICE LEAGUE movies. The calendar is a bit tricky.” Roven continued, "Of course, the script obviously has to be worth of him wanting to direct it. And once that happens, it’s still got to fit into the calendar. We’re hoping we can make it happen. We’re just at the beginning of the question."
"Look, if I could make it work, yeah,” Affleck said. “Obviously it would be like a dream. The trick is, as to any movie, is to make sure that you – if you’re going to direct it – that you can make it good. You’ve got to have the right idea and the right take on it. Broadly speaking, it’s something I’d be open to, for sure. It’s a very exciting idea."
Since these quotes come from TOTAL FILM's BvS set report, I'm going to assume that these quotes date back to 2014. And if that's the case -- and I'm pretty sure it is -- then it's very like lots of things have changed since both Roven and Affleck said the above.
I think it's VERY safe to say that when Warner Bros. gets around to making another solo Batman film, Ben Affleck will both direct and portray Batman in it. Heck, I think it's already a done deal. However, I do agree with Roven about Affleck's schedule being tricky -- I've been saying that for a while now and it's why I've never bought into the 2018 rumor. I think 2019 or 2020 are the most likely release dates for the solo Batfleck Batflick.