The singer/actress, who plays the title character, was admitted to rehab last year (10) to address undisclosed personal problems and she was written out of the programme when it became clear she would not be able to return to filming in January (11).
Disney bosses insisted Lovato's departure was temporary and she would be able to rejoin the cast once she was well enough.
But it has now emerged the show's name will be changed to So Random for its third season, fuelling rumours Lovato's exit will be made permanent.
Her co-star Brandon Mychal Smith says, "With a show like ours, and any great show that I've seen in the past, like The Wire or Seinfeld, each season you focus on a different concept, a different theory, or maybe a different character's background.
"Season one we established who we were - you saw some mini sketches, you saw who the characters were and how they mingled and intertwined. Season two you were able to see more of the relationship between Sonny and Chad and how they got into it and how we didn't like it, and you saw some of Mackenzie Falls and that aspect.
"And now this season you'll be able to see So Random, see why we are where we are today in regards to being the teen idols that we are. You'll be able to see how we bring the funny (sic) every week."