Alex Sandro has been subject to a bid by Italian champions Juventus.
The Porto full back has been at the club since 2011 and Juve are chasing the Brazilian international to strengthen their defence.
According to Sport Mediaset, the Bianconeri have submitted an offer of €15 million plus bonuses to Porto for Sandro.
It is believed, however, that Porto are looking for a figure of €20 million for Sandro.
This fee could be lowered should Juventus include Fernando Llorente in the deal, a player who Porto are interested in signing.
Llorente struggled last season, with Carlos Tevez and Alvaro Morata the preferred attacking partnership for Juventus.
With Euro 2016 at the end of next season, Llorente may be willingly to leave Juve in order to get regular first team football and thus boost his chances of representing Spain at the championships.
