FC Twente chairman Joop Munsterman has dismissed reports that Fulham have made an offer for Douglas, and warns suitors that the player's cost will be inflated by agent's fees.
Newcastle are also amongst a host of European clubs believed to be interested in the centre back, who has played 129 times for the Dutch club in five seasons.
Fulham have been tracking the Brazilian born player for some time, in a bid to bolster a central defence containing only three senior players. It was believed that Martin Jol's team had lodged an offer for the 24-year-old defender, but Munsterman was quick to dispel the rumours.
"[It's] absolutely not true [that an offer was received from Fulham]. We didn't receive a bid at all," Munsterman told reporters.
"Media are writing that we want to sell Douglas because he's out of contract in a year, but that's not true."
The chairman went on to indicate that the fee they require for Douglas – who is out of contract next summer and open to a move to England – will be affected by the high price of the player's agent.
A potential move to Fulham has emerged in the media recently due to the changing status of the player's nationality. From August 26, Douglas will have lived in Holland for five years, awarding him a Dutch passport that will allow him easy access to England via a labour permit.
Having been selected in Louis van Gaal's preliminary squad for his new country's game against Turkey, Douglas may soon start making headlines in a Holland shirt. Munsterman is keen not to let go of his star defender without a fight.
He continued: "We won't agree with these kind of offers. To us it's not about losing a player on a free agent, but what the result is after we've paid agents and such."