Jurgen Klopp may not have any fit senior centre backs for Liverpool's Premier League clash with title rivals Tottenham on Wednesday night.
Joel Matip was taken off at half-time of the Reds' 1-1 draw with Fulham on Sunday due to a back spasm and Klopp revealed on Tuesday he is unsure whether the 29-year-old will be fit.
Liverpool are already without Virgil van Dijk and Joe Gomez, who both sustained long-term injuries earlier this season, and are using midfielder Fabinho as a makeshift defender.
When asked about Matip's condition in his pre-match press conference, Klopp said: 'I don't know yet. He left (the Fulham game) with a back spasm.
'The physios are on him 24 hours so we will see.
'We have another session today so we'll see.'
Klopp may be forced to use youngsters Nathaniel Phillips or Rhys Williams alongside Fabinho if Matip is unfit.
It would be a serious blow to Liverpool's chances of winning the game, given they are going to come up against one of the league's best attacks in Harry Kane and Son Heung-min.
Klopp may also be without Naby Keita, who is still touch and go after his latest injury setback.
The German added: 'Naby is a maybe. Yesterday (Monday) he was involved in the extended warm-up.
'No-one else (will be coming back). Naby has no rhythm, that's the truth. That makes it difficult.'
More to follow.