Jamie Carragher is adamant that his former club Liverpool must sign a central defender in the January transfer window.

Joel Matip was forced off with an injury during the second half of Liverpool's 1-1 draw against West Bromwich Albion on Sunday, with defensive problems mounting for manager Jurgen Klopp.

The German may have to rely on youngsters Nat Phillips, Rhys Williams and Sepp van den Berg for the short term, but Carragher believes Liverpool have to buy next month if they are to retain the Premier League title.

"It is a massive worry but it is not a new worry. That is why it is paramount Liverpool sign someone in January," Carragher told Sky Sports News.

"I said that as soon as Virgil van Dijk had his injury. Fabinho has looked like a top-class centre-back, but Matip is just too injury prone. His body just can't take the rigours of playing in the Premier League week in, week out.

"I still believe Liverpool are the best team in the league even without Van Dijk. The only way they don't win it is if they have problems at centre-back where Rhys Williams or Nat Phillips have to play for a prolonged period. It's not a position for young players. At times they will make mistakes because they are young and learning. They have to do something in January."

Liverpool have one more match in 2020 away at Newcastle United on Wednesday before next month's transfer window opens on January 2.