User blog comment:Rassilon of Old/Young Justice spoilers at Comic-Con 2012/@comment-119.30.38.88-20120717065307/@comment-34954086-20120717144451

Back to comics Nightwing used to be on the League, he decided it his place was more solo hero, bat-family and any other Teams he became a part of. It's only a downgrade if the character thinks it is, being team instead of league would probably be considerred an upgrade for some heroes. Though i agree that Zatanna most likely wont leave the league until she gets what she wants out of it.