From Ryan Stewart at Cinematical:
Angelina told me that the project is still on the table, but "the thing with Atlas is just, we all feel that it's one of those projects where if you can't do it right, you really can't touch it. So we have not had all the pieces come together. There's not been a director that's right to come on, or all of those elements. So until it does, you know, I certainly don't want to be a part of something that's just put together to hit 'this date.'"
Given my expectation that the movie will suck, I don't see this as bad news. But at least this kind of delay indicates that someone is taking the book seriously, rather than as a star vehicle.
(Hat tip: Mack Rawden at Cinema Blend)