Zenit maintain that Axel Witsel is not for sale unless a club meet his €100 million (£72.8m) release clause.
The 26-year-old has been linked with a move to Tottenham, while Goal understands that the midfielder was on Chelsea’s shortlist earlier this summer.
AC Milan have also signalled their interest in the Belgium international but admit a deal would be difficult to finance, while the player himself claimed in June that he had been in talks over a switch to Juventus.
“The Belgian is still a Zenit player, the amount for his release clause is €100 million,” said a statement fromTASS, Zenit’s press service.
The Russian transfer window closes on August 31.