The highly-rated Costa Rica international forward had been strongly linked with Tottenham and Harry Redknapp admitted his interest, although added he was not a top priority.
However, Ruiz has now revealed that a deal with Fulham could be on the cards.
The 26-year-old told De Telegraaf: "Fulham is a serious option for me.
"That is also a Premier League side and it is a fantastic league.
"Fulham already contacted my agent. If Fulham does become serious, we will definitely talk."
Ruiz has been linked with a number of clubs this summer, but he insists he is not worried about his future.
"It makes no sense to worry, because I can't do anything about it," he said.
"Of course I want a step forward, but believe me I don't have any problems for a longer stay at FC Twente. FC Twente is a fantastic club."