I'm quite sure that she is playing for another team, I saw it in the last part of "Asian F". I think it's Shane( I don't know if this is her bf's name) who persuaded her to do so.
From 'Asian F', te can see she told Shelby that she wants to unisciti her Glee Club. From spoilers of the upcoming episode, the Sugar Motta Glee Club, the one Shelby is directing, is called Pot of Sugar & te will see Mercedes and Santana forming part of it.
