Liverpool have been urged to move for a centre-back in the January transfer window after being told they can no longer rely on Joel Matip.
Matip suffered another injury setback when he limped out of Sunday's 1-1 Premier League draw at home to West Bromwich Albion with an adductor problem.
Fitness concerns have restricted the Cameroonian to just eight starts this season, with Liverpool already missing long-term centre-back absentees Virgil van Dijk and Joe Gomez.
And former Liverpool defender Stephen Warnock believes Matip's regular issues mean Jurgen Klopp must move in the market next month.
"I personally feel that they will have to go into the transfer market," he told Sky Sports.
"You have Rhys Williams and Nat Phillips as backup, but you cannot rely on Joel Matip.
"His injury record since he joined Liverpool (means) he misses far too many games. He is injury prone.
"You can't rely on him for a consistent run of 10-15 games. You always feel is going to break down at some point.
"We know Liverpool have had huge problems missing Van Dijk and Gomez.
"But you need a decent backup pairing (at centre-back) you can rely on and they can't rely on Joel Matip."
