Newcastle United boss Rafa Benitez is sweating on the fitness of defender Deandre Yedlin.
The American international was forced off through injury during Newcastle's season opener against Tottenham.
WIth only a handful of minutes remaining, the full-back was forced to withdraw after landing awkwardly while trying to stop the ball going out of play.
Fans were immediately concerned, and more so when Yedlin was reported to have left the ground on crutches.
But Rafa Benitez has confirmed that the extent of the injury is still to be assessed - although he did reveal that Yedlin had injured his knee.
Any long-term absence would be another blow to Newcastle, who are already set to be without Florian Lejeune for an extended period.
Javier Manquillo would be able to deputise at right-back, but it would leave Benitez very short in the full-back areas.
For now, however, the Spaniard will have to wait patiently until doctors reveal the extent of the injury.
"It's a problem with his knee," said Benitez.
"We still have to wait for the doctor to asses it."