Why would Bayern even sell? They're not in the business of selling their best players (and no, the pig farmer was already showing signs of wear and tear when they disposed of him).
Obviously I'm kind of angry about all the bullshit Vidal has been saying about us ever since he left, but he'd walk into every starting 11 in the world, except for maybe Roma because they have his identical twin in Nainggolan and he has built himself quite the status in Rome. Even then they'd probably just play both tbh.