User blog comment:Rassilon of Old/Young Justice spoilers at Comic-Con 2012/@comment-98.70.76.153-20120803162748/@comment-1635895-20120805030249

We don't necessarily know that Jason wasn't Robin during the five-year gap. There are a few designation numbers left open, he could have filled one before his death. depending on when Dick became Nightwing, there could be a year or two in which Jason became Robin, joined the Team, and then was murdered. And then that comment Dick makes to Tim about not dying could be seen as a reference to Jason, and I believe there was one other possible reference which I can't think of now.

It would definitely be interesting for the Light if Ra's has Jason's corpse, who knows what they'll do with it...