Everton could be without Lucas Digne for a prolonged spell after he suffered an ankle injury in training.
The club are awaiting a full diagnosis on the severity of the problem, the PA news agency understands. There are concerns that he may require surgery.
Reports in his homeland have claimed the France left-back could be out for two months. Indeed, Everton have since confimed that he has suffered ligament damage.
Digne has missed only five Premier League matches since he joined the club in the summer of 2018 from Barcelona for £18million.
Last season, he started 35 games in the league, providing seven assists. He already has four assists to his name from eight league appearances this season.
If he does miss two months, he would be unavailable for their busy Christmas schedule. He could miss games against Chelsea, Arsenal, Manchester United and Manchester City, among others.
Andre Gomes on road to recovery
Meanwhile, Everton midfielder Andre Gomes admits he is still trying to get back to full fitness after his horrific fracture dislocation to his right ankle 12 months ago.
“The truth is, I am still trying to find my best feeling, to get fit, to get ready to be 100 per cent for all the game,” the Portugal international told Everton’s matchday programme ahead of Saturday’s visit of Leeds.
“In the past months, with the pandemic, it was hard for me physically.
“When we came back after the first lockdown, I had a really small injury in one place, then something else in another place, because I was trying to compensate coming from the big injury.
“I came from a big injury and tried to get in perfect shape and feel really good on the pitch and work on that.
“It is part of my job to do my best to get back in the side. It has been hard this season.”