The 27-year-old, who arrived from Twente in 2001, has largely struggled in the Premier League thus far. However, Jol has vowed to use Ruiz in his favoured position in the new campaign.
"Bryan wore number 11 last year because someone else had the number 10 but I think he is a typical number 10. He can play as a midfield player and he can play as a second striker," he told reporters at a press conference.
"I have to say in one of our games at the end of last season he scored two goals and then I played him on the right and he played in Holland of course in a different system on the right. Bryan Ruiz is an offensive quality player who can play in three or four positions."
Fulham were 3-0 winners over Cartagines in their first match of pre-season on Sunday.