The chairman of the board Pinto da Costa is afraid that some of the key football players may leave the team this summer.
On Tuesday, the Portuguese champions lost their coach Andre Villas Boas, whose contract was bought out by Chelsea for 15 million euros.
Now, the attention of English teams is focused on midfielder Joao Moutinho and striker Radamel Falcao.
"Since there are buyout clauses in the contracts, we must be prepared for some players to leave if someone offers enough money," da Costa said. "We don't want to negotiate with anyone. Just like with Villas Boas, we will simply provide the bill and wait for the money."
The Porto director added that there have been no specific talks about individual players yet.
Both Falcao and Moutinho's contracts can be bought out for 30 million euros.