Valencia are negotiating with Benfica for Enzo Perez but reports in Spain say the clubs are €5m in their valuations of the midfielder.
Sport cites a report from Portuguese publication Record which claims the only firm offer has come from Los Che, despite rumours of interest from Juventus and Manchester United.
Valencia have recently been taken over by Peter Lim, who is being advised by Portuguese agent Jorge Mendes. Mendes is said to be the driving force behind the move for Perez.
Perez signed a new Benfica deal in late May and has a release clause of €30m, having been part of the Benfica team that claimed a domestic treble last season.
The 28-year-old Perez has been at Benfica since 2011 and is part of Argentina’s squad for the World Cup.
