Spurs star Dele Alli has been ruled out of the start of the new season with a hamstring injury.
The England international picked up the problem in training and boss Mauricio Pochettino has confirmed he won't be fit for Saturday's Premier League opener against Aston Villa.
It will come as a big blow to Alli, 23, who was beset by hamstring problems last season and Pochettino admits it is a concern.
The Argentine, who saw Spurs end their pre-season campaign with a 1-1 draw against Inter Milan yesterday, 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 hamstring problems in the last few years.
"But we are here to try to help him. I think it is a minor injury. Only a few weeks before he can be available again."
With the transfer window closing at 5pm on Thursday, Tanguy Ndombele remains Spurs' only signing and Pochettino expressed his frustration last week when he distanced himself from the club's dealings.
He offered no new updates on potential incomings, with Giovanni 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 Frenchman did not have a massive impact, beyond an exciting dart into the penalty in the first half.
Pochettino has warned that 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.
"Of course it's only him who arrived to the club and that makes it more difficult.
''When a few are new they can help each other but it's only him.
"We need to give him time but I am happy in the way he is adapting.
''He is open to improve and learn but he obviously needs more time to see the best version of him."