United are preparing a £37m bid but Old Trafford legend Neville has his doubts that the Spain star is the answer to their problems.
Neville told the Daily Star: "That's a lot of money, 37 million quid, but they need a signing.
"Does he fit with what I would call the typical philosophy of Manchester United? I would say no.
"The first question, I think, is where are you going to play? Wayne Rooney and Robin van Persie are up top if they are fit so where are you going to play him? Are you going to play him off the left or off the right?
"We've seen Kagawa play off the left, we saw Kleberson play at times off the left, we've seen Veron at Manchester United move to the left because you can't play central midfield.
"Maybe they have to change the philosophy and maybe that's what David Moyes is thinking.
"Maybe he wants to play narrow wide players and maybe a three in midfield.
"They would have to change to accommodate Juan Mata in the way they normally play."
Neville added: "He's obviously a fantastic football player, there's no doubt about that, but one thing it does do, I suppose, is that David Moyes, Manchester United and Ed Woodward need to sign a big player.
"They need to make a noise and if they get him in it will attract potentially other players - and they need three or four players.
"What it could be is the start of something to lead to other things, but typically I wouldn't say he fits."
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