Monk claims the World Cup runner-up's pedigree means the near £8m price-tag won't weigh heavy - and the fee is a snip compared to other British deals as he seeks further new faces in the remaining ten days of the transfer window.
He said: "It is an important signing for us. Obviously Chico (Flores) left and it was important that we filled that gap and Federico more than does that.
"He is an Argentina international, has played at a very high level with Napoli and was highly considered over there. He has just played in the World Cup so he is a very good signing and a sign of the progress the club is making.
"This guy has played in a World Cup for Argentina, he has performed well in Serie A for Napoli and when you look at it like that it is not much money at all. A price tag is not something that will hang around him because the money spent elsewhere is ridiculous. I understand that may be compared to us as a club when we haven't spent big fees over the years but when you put it in perspective, I think it is a good deal."
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