Liverpool are worried that they may be without centre-back Joël Matip for up to a month with a thigh injury - leaving them with limited options across a hectic fixture schedule.
The Reds defender has been ruled out of the trip to Brighton & Hove Albion on Saturday with a muscle issue which he sustained in the win over Stoke City in mid-week.
That leaves Jürgen Klopp with only Dejan Lovren and Ragnar Klavan, absent from the victory over the Potters due to illness, as his senior central options - and Liverpool are worried Klopp will be without Matip until the New Year.
The full extent of the former Schalke man's problem has yet to be discovered, though reports suggest he is unlikely to feature again until 2018 - leaving just Lovren and Klavan.
Joe Gomez, who starred as the right-sided centre-back in a back-three for England last month, could be moved centrally - though that would leave only Trent Alexander-Arnold at right-back with Nathaniel Clyne out for at least the next couple of months.
Gomez has played all of his minutes for Liverpool this season on the right, having regularly shared full-back duties with Academy graduate Alexander-Arnold - but is seen as a centre-back in the long term.
Liverpool facing frantic Christmas period without best centre-half
The expected severity of Matip's injury is a major blow as Liverpool's best centre-back and approaching a run of nine fixtures within just 30 days, including crunch Premier League clashes with Everton and Arsenal.
The Reds also have a crucial Champions League showdown with Spartak Moscow next Wednesday to determine whether they will be involved in the competition's knock-out stages in February.
The Cameroon international's niggling injury problems also caused him to miss 10 games last term while a thigh injury last month meant he missed more games, including the win over Southampton, this season.
Another huge worry will be Lovren's tendency to pick up small injuries. The Croatian missed the draw with Chelsea with a knock and has missed a handful of matches in each of Liverpool's last few seasons due to slight problems.
Having failed to sign Virgil van Dijk, his only centre-back target in the summer, Klopp could be forced to seek recruitment in the January transfer window.
But Liverpool have plenty of games to contend with before then, meaning Klopp will have to manage his squad carefully and could be forced to utilising makeshift centre-backs - or promoting youth prospects - to keep his players fresh.