I doubt if Chelsea really want to sign Maguire. There is nothing special about this player, he is just a controversial defender. I'm sure it is a rumor only, Chelsea will never try to negotiate with Man United to sign Maguire. Anyway, I agree that Maguire is better to leave Man United because he is probably difficult to get a chance playing regularly there. Not sure which team is serious to sign him, but he should leave if there is an offer from other teams. His career won't be better if he stays in Man United, he can't compete with Varane and Martinez.