The £5million summer signing from AZ Alkmaar has impressed since his arrival at Craven Cottage and now has a crucial role to play.
With Andy Johnson still several weeks from a first-team return following his battle with a knee injury and Zamora out for four months, Dembele has become a key player.
"We hope Moussa can get the goals - there's a big onus on him now that Bobby's gone," said Cottagers boss Hughes.
"But it's a big ask, you can't just hang a hat on Moussa. He'll get good support from the guys around him and that will help him become the success we think he will be.
"The beauty of Moussa is that he can play in a number of positions.
"That's the attraction from my point of view because I like players who have that flexibility."