Tottenham face being without striker Harry Kane for at least 10 games after it was confirmed the England captain had damaged ligaments in his left ankle.
Kane suffered the injury during the final stages of Spurs' 1-0 defeat to Manchester United at Wembley on Sunday, after being caught in the middle of Phil Jones and Victor Lindelof.
The initial prognosis from Tottenham's medical staff suggested early March as a potential date for return to training.
The loss of leading scorer Kane, who has 20 goals so far this season, represents a huge blow to third-placed Tottenham's titles hopes, with Mauricio Pochettino's side now some nine points behind leaders Liverpool.
A statement on the club's website read: "Following preliminary assessments, we can confirm that Harry Kane has damaged ligaments in his left ankle, sustained during Sunday's match against Manchester United.
"The striker will continue to be monitored by our medical staff as he commences rehabilitation and is expected to return to training in early March."
It is the third successive season in which Kane has suffered an ankle injury, the most recent one keeping him out for a fortnight last March.
Kane is now set to miss the second leg of the Carabao Cup semi-final against Chelsea, which Spurs lead 1-0, on January 24, as well as the first leg of the Champions League last-16 tie at home to Borussia Dortmund next month.
Spurs will also be missing their star man for at least six scheduled Premier League matches, including the trip to Stamford Bridge on February 27.
Kane is also highly likely to be unavailable for the north London derby against Arsenal on March 2 and the return meeting with Dortmund three days later.
Kane responded to the news of his injury on Twitter, and said: "Injuries are part of the game but no-one will be working harder to get back fit. Thanks for the messages."
The lengthy absence of Kane is also set to leave Spurs short of attacking options heading into a crucial phase of the campaign.
Son Heung-min is away on international duty with South Korea at the Asian Cup, Lucas Moura is also still injured himself, while Fernando Llorente and Vincent Janssen are both expected to leave the club this month.
The England captain, though, could well be back in contention for the opening Euro 2020 qualifier against the Czech Republic on March 22.