Okay let's rule out those who won't be Robin:
- Tim Drake. He's Red Robin, he's his own man now, is the leader of the Titans. Going back to being Batman's boy wonder is a step back for the character. And judging by his recent portrayals, he doesn't seem to be interested in being a sidekick again.
- Harper Row. She's going to be Bluebird, and she's too rebel to be a full fledged sidekick anyway. Also, didn't Snyder confirm that she won't be Robin?
- Stephanie Brown. At least in the Robin Rises story-line she won't be. Her only appearance in the New 52 is in Snyder's series, and whoever will be the new Robin is going to be revealed in Tomasi's series, and the writers are trying to make each Bat Book separate from the other. In BE, she hasn't even fully become Spoiler yet, so I doubt she's going to be Robin. Could be somewhere down the line,make her tenure as Robin last more than the Pre-Flashpoint era, which was barely a cup of tea, but definitely not in this story-line.
- Carrie Kelly. Her only ties to Bruce is the fact that she was Damian's teacher. Otherwise she has no ties to Batman and doesn't have any motive for being Robin. She seems to be a normal teenager living a normal life. I am interested in seeing more of her though.
So there are two choices. It'll either be Damian, which is too obvious so there'll probably be a twist maybe he loses his memories or something, or it'll be a new character introduced on Apokolips, which I really hope isn't the case.