Dembele has become a key player for Spurs since his deadline day move from Fulham, but he has missed the club's last eight games with a niggling hip problem.
The Belgian had hoped to return for Saturday's crunch match at the Emirates Stadium, but manager Andre Villas-Boas has ruled the playmaker out of the game. "Dembele does not have a chance, not for this game," Villas-Boas said.
He added: "There is a 50% chance he will be back for the Lazio game. I think surgery at the moment is out of the question, hopefully."
Jermain Defoe, Aaron Lennon and Kyle Walker all suffered hamstring injuries in last weekend's 2-1 defeat to Manchester City.
Lennon appears to have been given the green light to play against the Gunners, but Villas-Boas is unsure whether Defoe and Walker will be available.
"They haven't trained with the team yet. They have had lighter sessions on their own," Villas-Boas said of the trio.
"We will have to see today how they return to see if there's any disturbance.
"Lennon had a scan yesterday, and it's fine on his hamstring."
Villas-Boas is already without long-term absentees Scott Parker, Benoit Assou-Ekotto and Younes Kaboul.
Source: PA
Source: PA