Jose Mourinho has confirmed that Son Heung-min is unlikely to feature for Tottenham Hotspur against Manchester United.
The influential attacker was substituted at half-time during Spurs' 1-1 draw with Newcastle United.
With Spurs having a hectic schedule and Son having featured in all of their games so far this season, it was speculated that he was withdrawn in order to get a rest ahead of upcoming matches.
Yet Mourinho confirmed that the South Korean will be out of action for the foreseeable future due to injury.
He told the Mirror: "It's an injury.
"We'll have him out for a while. It's his hamstring."
It comes as a huge blow for Spurs, with Son having been in excellent form so far this season.
Spurs conceded a controversial late penalty against Newcastle to draw 1-1 despite dominating proceedings.
It means they have won one, drawn one and lost one from their opening three Premier League matches this season - already placing them under pressure ahead of facing United next weekend.
Yet, due to their Europa League campaign and the Carabao Cup, Spurs face a hectic schedule ahead of even facing the Reds next week.
They face Chelsea in the Carabao Cup on Tuesday before hosting Maccabi Haifa in the Europa League just two days later - and then a game against United follows on Sunday.
It means Spurs' squad will likely be stretched to the limit over the next week and there could be some pressure on to bring in reinforcements in the transfer market ahead of United.
Son's absence will place further pressure on Gareth Bale to return quickly from an injury he picked up on international duty earlier this month for Wales.
Bale, previously linked with United, is yet to feature for Spurs since joining on loan from Real Madrid.