FC Porto president Pinto da Costa has insisted that one-time Chelsea target Alvaro Pereira is not for sale.
The full-back was heavily linked with a switch to Stamford Bridge during the summer but a move never materialised.
Speculation has suggested that the Blues are preparing to renew their interest next month.
However, Da Costa has told Chelsea that they would be wasting their time by submitting an offer.
"I have offered a guarantee to the coach that no important players will leave the team in January, and that includes Alvaro Pereira," said Da Costa.
"I think the chance to do a deal for this player has passed, and that is good news for us.
"Now is the time that rumours start spreading in the papers, but I am used to that."
Pereira, 25, joined the Portuguese club in 2008 from CFR Cluj.
