Clubs interested in signing Bruno Fernandes have been told by the club's president that they will have to pay more than the £31m in his release clause.
The Portugal international has been touted as a target for Manchester United, Liverpool and Tottenham Hotspur in recent weeks.
Fernandes caught the eye in the Primeira Liga last season with 20 goals and 13 assists across his 33 appearances.
Amid the growing interest in his side's prized asset, Sporting president Frederico Varandas has warned it will cost more than £31m to land the midfielder.
"It's obvious that he will be wanted by big clubs," he told Sporting TV. "It doesn't imply that he leaves. It's also not a drama if he leaves.
"If he stays, Sporting have plan A; if he leaves, we have plan B. If in the market they want Bruno Fernandes, it must be a heavy amount."
Fernandes spoke about his future while on international duty with Portugal earlier this month, admitting that he wants to further his career elsewhere but is happy to bide his time.
