Berbatov has flourished since moving to Craven Cottage to reunite with his former Tottenham boss - he's managed five goals and three assists already - and left many wondering why other clubs didn't try to sign him from Manchester United during the summer.
Jol lost two key players in August when Mousa Dembele and Clint Dempsey joined Tottenham, but he feels the Bulgarian will stay put until his contract expires in 2014.
When asked if he would offer the 31-year-old a new deal in January, Jol said: "He has two years - this year and next - and that is enough. As long as I am here so will he be."
Meanwhile, the Fulham manager is yet to make up his mind about whether to sign on-loan Cologne defender Riether permanently.
The German has been an ever-present since his arrival in west London and Jol admits he's been surprised by the right-back's impact.
Speaking about the possibility of signing Riether permanently, Jol added: "Wait and see. He's good, he was a big surprise."