User blog comment:Dtregle/Jason Todd in Young Justice/@comment-5154078-20120617232957/@comment-1038387-20120731074703

Nope. There's no room for Jason in the timeline.

There's a five year timeskip, January 2011- January 2016


 * Tim appears as a Team member in Legacy, which plays around December 2014/January 2015. So essentially, the timeframe for Jason's appearance is reduced to four years.
 * Dick has to become Nightwing first before a second Robin can come into the picture. We don't know exactly when he does that. He was fourteen at the end of season one. To be nightwing fifteen, sixteen at least, but more likely seventeen. So that makes ~October 2013 (or whatever his birthday is)/January 2014.
 * Leaves the slot for Jason of about a year, at most. And that's stretching it.
 * They would not be so jovial about "just don't die" in "Happy New Year" if Jason had died.

So, I rate the chances of Jason showing up as "ferociously unlikely". The timeline is friendly to a Damian appearance, though.