Before I start, I am calling this a rumor because there isn't a whole lot of substantial evidence backing this up. Take this with a grain of salt. I'm not calling Batman-on-Film liars by any means; however, let's hope that Warner Bros. eventually releases some news to back this up.
Anyway, Batman-on-Film claims to have a source within Warner Bros. saying that Batman is a huge asset to Warner Bros., and if a Justice League movie is bad, they might lose the Batman fanbase they currently have.
So the Batman reboot depends on the Justice League getting scrapped and the Man of Steel trilogy doing well. (Yes, apparently it's supposed to be trilogy now.) Assuming that the new Man of Steel does well and is actually a trilogy, Batman will be released around 2019 or so.
So to clarify, Batman was supposed to happen after both Man of Steel and Justice League. But with the recent news around Justice League, it might be bumped up sooner than expected.