Maddison has been "jettisoned" because his contract is at an end and, given the player has long considered himself above Posh, there's no point in offering him a new one. He's expecting a Championship role on a 5 figure weekly wage. So a long way out of our wage structure and a disruptive influence as well.
Maddison as well as Cooper was out on loan, suggesting there's no automatic place at Posh for George.