Birmingham insist it is they who have the final say on the future of striker Christian Benitez.
Blues took the Ecuador international on loan last summer and are thought to have agreed a fee of US$8million - just over £5m - with his club Santos Laguna for if they wish to make the move permanent at the end of this season.
Benitez, 23, recently revealed that Santos Laguna had been contacted by two other Premier League clubs about his availability this summer.
But Birmingham are adamant the agreement they struck with the Mexican club means they have first refusal on Benitez, regardless of whether another club is now willing to pay a higher fee.
"We have a date by when we have to decide whether to sign the player," Blues' vice-chairman Peter Pannu told the Birmingham Mail.
"What is being said elsewhere, what is happening in Mexico or if other Premier League clubs have come in, I don't think it is right for me to comment on that.
"We have a contract and, even if Santos Laguna accept $15m, so what? It doesn't affect our decision."
Benitez, who wears his nickname 'Chucho' on the back of his shirt, has only scored two goals in 20 Premier League starts but has still been a valuable asset in the Blues' attack.
"(Manager) Alex McLeish will decide whether we exercise our option and we will respect and support him on that," Pannu added.
"If Alex thinks Benitez fits into the master plan, then he has a pot of money to dip into.
"If he recommends that we don't exercise the option, then so be it. His club can then freely send Benitez to the North Pole, Bangladesh, anywhere.
"We will know about Benitez's future in due course. We have not heard from Alex yet about him. The season is not over."