The England international picked up the problem in training and manager Mauricio Pochettino has confirmed he will miss their opening game of the campaign against Aston Villa next Saturday.
It will come as a big blow to the playmaker, who was beset by hamstring problems last season and Pochettino admits it is a concern.
The Argentinian, who saw his side conclude their pre-season preparations with a 1-1 draw against Inter Milan on Sunday, said: “I don’t believe he’s going to be ready for the start of the season.
“It’s the same area. Yes, of course we are worried. He’s still so young. Just 23 and many, many hamstring problems in the last few years.
“It’s to pay attention to what is going on in his body, but we are here to try to help him. I think (it is a) minor injury. It’s only a few weeks before he can be available again and be with the group.”
With less than a week until the transfer window shuts, Tanguy Ndombele remains the only signing that will impact the first team this summer and Pochettino expressed his frustration last week when he appeared to distance himself from the club’s dealings.
He offered no new updates on potential incomings, with Giovani Lo Celso and Bruno Fernandes reported targets, and has not spoken to chairman Daniel Levy in recent days.
“No, he’s in Miami and I didn’t have the opportunity to talk to him,” Pochettino said of Levy.
“I am happy with my squad. You can see today a lot of younger players. In every season we are always open to improve the squad and to try to find the right players to be stronger and better and there are still four days.
“We’ll see what happens in the next few days.”
Spurs fans got their first look at new record signing Ndombele, though the France midfielder did not have a huge impact, beyond an exciting dart into the penalty area in the first half.
Pochettino has warned the midfielder will need time to get used to English football.
“For him it’s difficult,” he said. “We cannot expect too much. We need to accept he needs time to adapt to first a new culture, a new country, new habits.”
