Tottenham will assess Kieran Trippier on Monday after he limped off during their friendly victory over Juventus at Wembley.
The injury scare threatened to overshadow an impressive 2-0 victory for Spurs with just days to go until the start of the new Premier League season.
Tottenham sold right-back Kyle Walker to Manchester City this summer knowing they had a high-class right-back option in Trippier, signed from Burnley two years ago.
But the 26-year-old lasted only 41 minutes after twice being hurt in tackles with Alex Sandro.
The first came after only four minutes but Trippier was able to continue and set up the opening goal for Harry Kane.
But he went down again five minutes before half-time and this time was forced to leave the pitch for good, with Kyle Walker-Peters, a 20-year-old with no Premier League experience, replacing him.
And Mauricio Pochettino confirmed after the game the damage Trippier suffered will be assessed on Monday.
“We don’t know how serious it is yet. We will wait until Monday but the feeling at the moment is good,” Pochettino told reporters at Wembley.
“I cannot guess if he will be ready for Newcastle.”
It was a sour note on an otherwise uplifting afternoon for Spurs, with Christian Eriksen also netting in a 2-0 victory.