IndieWire says

While much of the casting chatter in recent weeks surrounding "The Hunger Games: Catching Fire" has been around who will play Finnick Odair in the highly anticipated sequel, there are still more key characters to be cast. And some names are beginning to emerge for who might take the crucial role of Johanna Mason in the film. (Cinema, Mia Wasikowska, The Hunger Games: Catching Fire, Zoe Aggeliki)