Jol’s side have been heavily reliant on Dimitar Berbatov and Bryan Ruiz to produce the majority of their goals this season, with Steve Sidwell top scoring from midfield.
Dempsey, 29, completed a £7m switch to Spurs on the summer transfer window’s deadline day after scoring 29 goals in 74 Premier League appearances for Fulham in the past two seasons.
And the Fulham manager reckons the Cottagers would be in the top half of the Premier League if his side still had the playmaker’s goal threat – Fulham are currently 13th in the table.
“Clint Dempsey always made the difference,” said Jol, whose side face Norwich on Saturday.
“I feel if Clint Dempsey hadn’t been here over the last three or four years, we could’ve ended up with a real problem.
“Our strikers never used to score a lot of goals. Now I think we’re fine, but we don’t have Clint. If Clint had stayed I think we would’ve been in the top 10.
“I feel we will score more goals than before, but we need the important and vital goals. Clint Dempsey scored all our winners last year.”
“We sold our top scorer and he (Dempsey) was the top scorer for a couple of years. Last year he scored more goals than any year before – and Dembele was my best player, arguably.
“We had to build a new team. If everyone is fit I still feel we’re not far from the quality we had last year.”
MORE: Man United latest news
MORE: Arsenal latest news
MORE: Chelsea latest news
MORE: Liverpool latest news