Liverpool defender Alberto Moreno could spend up to six weeks on the sidelines.
Moreno suffered an ankle injury during his side’s Champions League victory over Spartak Moscow which threatens to rule him out of the Reds’ festive schedule.
The Spain international is set to undergo further tests on the problem in the coming days and will miss Sunday’s Merseyside derby clash with Everton.
Andy Robertson is likely to deputise at left-back in Moreno’s absence, with Jurgen Klopp admitting that the extent of the injury remains unclear.
He said: “We need to have further assessment. So far it could be everything.
“I cannot say much about it. It’s a very rare thing. So far the specialists aren’t sure.
“But if it’s in a week or so or a little bit longer so we have to wait for that.
“There’s a little damage around the tendons.”
Moreno has enjoyed a surprise resurgence at Anfield this season since Liverpool rejected an £11 million offer from Napoli during the summer transfer window.