Glee cast members face the axe as Murphy wants the show to replicate a real high school with older students graduating and replaced by new faces.
Murphy has introduced Chord Overstreet as Sam Evans in the current second series to start the process.
“Every year we’re going to populate a new group,” Murphy says. “There’s nothing more depressing than a high schooler with a bald spot.
Murphy has nominated the end of the 2012 season of Glee as the likely time for cast exits.
Stars including Lea Michelle, Cory Monteith, Dianna Agron, Chris Colfer and Kevin McHale have all sprung to worldwide fame playing Glee students.
“I think you have to be true to the fact that here is a group of people who come and go in these teachers’ lives – they graduate and they’re gone,” Murphy says.
“When some of them finish their run at high school it will be very teary episodes.
“For me it will be particularly tough but a new crop (of actors) will come in.”
Glee has been averaging around 12 million viewers in the USA and around 1.3 million in Australia but you would expect that figure to rise significantly for any ‘farewell’ episodes.
Murphy says that he discussed ‘graduating’ core cast with Glee co-executive producer Ian Brennan and Brad Falchuk.
“I was concerned about that (whether to have characters graduate and leave the show) because those kids caught on so quickly – but I think one of the things I’m very happy we’ve been able to do this years is we’ve brought in new characters.”
“I think if you can keep regenerating – and I didn’t think we could – I didn’t know if people would want those characters (like Sam) but they do.”