Dembele has made only one start in all competitions this term and is now a doubt for Saturday's game at West Brom after his left, and striking, foot was stamped on in training.
The problem arose just as Dembele was ready to return from a hamstring injury picked up against Sunderland almost four weeks ago and after the Belgian missed the opening four matches of the season through suspension.
His latest setback is particularly concerning too, given it is a recurrence of the same foot problem that kept him out for five weeks at the start of last season.
"He had a minor problem in his hamstring against Sunderland
Then it was good but he got a knock in his foot, an old problem, and now he's recovering from that," Pochettino said.
"It was in training
It's minor but it's painful for him
When he touches the ball, it's painful for him."
Dembele was arguably Tottenham's best player for much of the 2015-16 campaign and any prolonged absence would be a blow to Pochettino, with crunch domestic and European fixtures coming up.
Spurs are about to face seven games in 23 days including home and away matches against Bayer Leverkusen in the Champions League, an EFL Cup fourth round visit to Liverpool and culminating in the north London derby against Arsenal on November 6.
Harry Kane could return from an ankle ligament injury for the game at the Emirates and there was better news regarding the striker's recovery.
"At the end of this week, maybe he can start to train and touch the grass a little bit
He's very positive, he's doing well," Pochettino said.
"We hope that next week he'll be training on the grass, on the pitch - still not with the group - but we're happy in the way he is recovering from his injury."
Source : PA
Source: PA