Skysports.com understands that Lucho Gonzalez is very high on Sven Goran Eriksson's wanted list at Manchester City.
However, Porto are asking for €20million (£13.5million) for their skipper and are unlikely to drop their price.
Valencia and Villarreal have both made offers, with Los Che understood to be willing to pay £12million - but Porto do not look like budging.
The 26-year-old Argentine international, currently playing in the Copa America, joined Porto two years ago but he now seems ready to move to one of Europe's premier competitions.
Valencia are leading the chase, but City are ready to join in, whilst a number of other English clubs including Tottenham, Aston Villa and West Ham are closely monitoring the situation.
Whilst remaining hot on Gonzalez's trail, Valencia insist they will not be forced into making a new offer.
"It is necessary to remain calm, we have many good players - there is no need to rush the negotiations," said Valencia sporting director Miguel Angel Ruiz.
City boss Eriksson looks as if he could bring in up to ten players before the season starts, but so far the club have only agreed a deal for Reggina front-man Rolando Bianchi.
Eriksson still has extensive links in Portugal following his spell as Benfica boss and it is believed that he is using his contacts to try and set up a deal for Gonzalez.