Zamora was carried off on a stretcher in the first half of Saturday's Barclays Premier League clash with Wolves at Craven Cottage after his ankle buckled under a robust challenge from Wolves midfielder Karl Henry, who has sent his sympathies to the England striker.
It was a major blow for both player and team alike, with Zamora's impressive leading of the Fulham attack having earned the 29-year-old full international honours.
Zamora has undergone surgery to repair a fractured fibula as well as ligament damage, but the player looks set for a prolonged spell on the sidelines.
Dembele - whose double, including a dramatic injury-time free-kick, secured victory over Wolves - admits Zamora is a big loss.
"In the dressing room, for me personally, I was in shock," the Belgian youngster said.
"Bobby is one of the most important players in the team and to lose him to injury is very hard for us. It is not going to be easy for us now."
With Andrew Johnson still several weeks from a first-team return following his battle with a knee injury, Dembele looks set to become a key member of the Fulham attack.
The £5million summer signing from AZ Alkmaar has impressed since his arrival at Craven Cottage, and manager Mark Hughes hopes the 23-year-old can help fill the void left by Zamora's enforced absence.
Dembele added on the club's official website, www.fulhamfc.com: "I will play wherever the manager wants me to play.
"We have a lot of players that can play up front and behind the attack. Against Wolves, Clint Dempsey and I split the work.
"It was important for us to keep playing our own game. We have the players to play nice football.
"All the big teams play their football and the other teams have to adapt - we should also do that."