Liverpool’s Trent Alexander-Arnold is expected to be sidelined for up to a month with knee damage, leaving the Premier League leaders short of defensive options.
The England international sustained a problem in the warm-up before Saturday’s 1-0 win at Brighton, but played the full 90 minutes.
However, he now faces an extended spell on the sidelines with a knee ligament issue.
Joe Gomez is still working his way back to fitness after a broken foot, and right back Nathaniel Clyne was loaned to Bournemouth earlier this month.
James Milner appears the likely candidate to start at the back in Saturday’s home game against Crystal Palace, although fellow midfielder Fabinho, who played centre-back at the weekend because Joel Matip, Gomez and Dejan Lovren are not fully fit, could potentially fill in.
Matip was an unused substitute against Brighton after recovering from a broken collarbone, while Gomez has yet to return to full training.
Midfielder Georginio Wijnaldum also sustained a knock to his knee at Brighton.
He is being assessed on a day-to-day basis and, while he has not yet been ruled out, he appears a major doubt for the Palace game.
Despite their injury concerns, Jurgen Klopp’s Premier League leaders still have the best defensive record, and midfielder Milner has singled out goalkeeper Alisson Becker as his player of the season so far.
The Brazil international, a summer signing from Roma, has kept 13 clean-sheets in 22 appearances, conceding just 10 goals in total.
“It’s hard to pick out one player because everyone in the squad has done so well, not just the 11 who are starting,” Milner told Liverpool’s official magazine.
“I think maybe one you could select is Alisson. Coming to a new league is never easy.
“He’s been unbelievable for us this season so far, and I believe that he’ll be a massive, massive player for us going forward,” Milner added.