Joel Matip's injury has made life difficult for Liverpool. The Cameroonian likely won't play again this season and may not feature for the Reds again, given his contract expires in 2024.
But that's the long-term consideration. For now, Liverpool and Jurgen Klopp need to figure out how they navigate the next month.
January, of course, offers some reprieve as a new defender could arrive. There's little suggestion that anyone will as of yet, but the opportunity will be there. Until then, Klopp's options in central defence are Virgil van Dijk, Ibrahima Konate, Joe Gomez and Jarell Quansah.
Van Dijk isn't a worry and will play every major game. It's who partners him that brings up questions.
Quansah has played well at times this season but is still very inexperienced. That's a worry given Liverpool play Manchester United and Arsenal at Anfield over the next few weeks, then Newcastle United make the trip on New Year's Day. There's an EFL Cup quarter-final against West Ham United thrown in for good measure, too.
All those games are a major step up for Quansah and arguably one that's too high at this stage. It makes him a fourth-choice by some way, leaving Konate and Gomez.
Gomez, though, is Trent Alexander-Arnold's primary backup at right-back. That's a more important role than ever as Liverpool have been moving the Scouser into midfield as of late, which necessitates bringing on Gomez. Klopp can't do that if the latter is at centre-back.
And so the clear favourite to partner Van Dijk right now is Konate. Having him there makes everything much easier and Klopp almost certainly hopes he can start against United, Arsenal and Newcastle. Possibly West Ham, too.
But that's where the headache comes in. Klopp has been using Konate sparingly lately, not wanting to play him too often because of the injury risk. He admitted as much after the win vs LASK.
"That we took [Konate] off was a medical decision," he said. "We took no risks, stuff like this. Give him minutes but not too long."
Konate subsequently started on the bench against Fulham, playing 21 minutes. Then came a start and full 90 minutes vs Sheffield United - where he impressed - before the Frenchman returned to the bench against Crystal Palace.
Liverpool are careful not to overplay Konate but they might be forced to this month. If they don't, they'll need to sacrifice elsewhere, be it experience or tactically. But if the risk proves to be too much, they could lose another defender when they really can't afford to.
It's going to be a headache for Klopp and co. as they'll need to manage Konate to near perfection over the coming weeks.