Tottenham and Inter Milan have been linked with Silvestre since the end of last season.
"It's no secret that he is liked by many great Italian and foreign teams," the club's new sporting director told Radio Radio.
"The most concrete interest has been shown by Inter. Silvestre, however, was a strong investment for Palermo, who paid 7-8m and so we cannot consider offers that are inferior to these. For now there has only been talk."