I actually can across this rumor a couple weeks ago, from a source that wasn’t very reliable. Now according to the official Injustice Twitter account, Barbra Gordon aka Batgirl has been officially confirmed.
Looks like the bat’s out of the bag. Batgirl is a playable DLC character in Injustice. Catch her gameplay next week! twitter.com/InjusticeGame/…
— InjusticeGame (@InjusticeGame) May 4, 2013
Batgirl girl is only the second character to be announced by the Injustice crew (Netherrealm), Lobo was the other character who was announced and is due out on 7 May.