The Brazilian thinks Maguire will be exposed for a lack of pace.
“In the World Cup he did a good job, but he’s going to have a few tough moments in one on one’s and his pace is not the best.
“United need to ensure he’s helped by a strong midfield, to help cover him and defend as a unit.
“I don’t know if he will manage to cover on his own like at times against Chelsea.
“Maguire has moved for a lot of money but I think the defenders aren’t as good in the league as they were a few years ago, therefore teams need to pay more.
“With Maguire and [Victor] Lindelof, I don’t know if [Chris] Smalling and [Phil] Jones need to leave but of course their opportunities to play will be a bit less.
“Especially as the new defenders have played very well in their first opportunity.”