The centre back has been subject to a lot of interest over the summer and Munsterman was forthright about the chances of Douglas leaving, claiming he will either leave now or depart on a free transfer next season.
He went on to state that no bid has been placed from either Premier League club, yet, many Dutch sources have said that a €5.5 million (approx £4.4m) offer from Fulham has actually been accepted. These reports also suggest the player will arrive in London on Thursday to undergo the infamously strenuous Fulham medical.
Talking to Voetbl International, Munsterman said: "Both clubs [Fulham & Newcastle] told us they want to do business with us.
"We [haven't] received any offers yet, but when they want to pay a fair price, Douglas may leave the club. Because otherwise he will leave Twente for free next year."