Who leaked to Novak beside ‘Official A’?

OK, so the indictment says that Official A leaked to Novak. But didn’t Novak say that he was leaked to by (at least) two people, one of whom was “no partisan gunslinger.” Assuming that Official A is Rove and that Rove cut a deal and rolled on Libby, thus keeping his shit clean (for now), who was the other leaker? I’m not saying that Novak couldn’t have just been flat-out lying. I’m just saying.