Losing top scorer Harry Kane for an extended period would be a "massive" blow to Tottenham Hotspur, admits manager Mauricio Pochettino.
Kane, the Premier League's joint top scorer with 14 goals, was limping heavily after colliding with Victor Lindelof late in Sunday's 1-0 loss to Manchester United.
He collapsed on the pitch at game's end and had to be helped off by Spurs medical staff.
Pochettino didn't immediately know the extent of the injury but admitted to being worried, especially with Son Heung Min, the club's second-leading scorer, heading off to join South Korea at the Asian Cup.
"My worry is that it was a bad tackle in the last moment," he told reporters.
"It wasn't the intention of the United player but it was a bad tackle and now he has a bit of swelling on his ankle and he was limping after the game.
"We are going to lose Son for the Asia Cup and if Harry Kane suffers an injury, it is going to be massive for us.
"Now we need to assess him over the next few days, hoping it is not a big issue."
Pochettino said both Kane and midfielder Moussa Sissoko, who limped off injured just before half-time, would be examined on Monday.
The loss kept Tottenham third in the table, nine points behind leaders Liverpool and just one ahead of Chelsea.