The Netherlands international suffered cruciate ligament damage after a tackle from Everton goalkeeper Jordan Pickford in last week's Merseyside derby and is awaiting a date for surgery.

Klopp now only has two fit senior centre-backs in Joe Gomez and Joel Matip, with midfielder Fabinho providing impressive cover in the midweek Champions League victory over Ajax.

Liverpool have refused to put a timescale on how long Van Dijk will be out but have not yet ruled him out of the whole season.

"We don't even want to know it, to be honest. It will take time, that's clear," Klopp said on Friday.

"In the end, it's really like this: all people are different and so we should not limit that by saying 'for him it was that long, for him it was that long'."

Klopp is hoping for some good news on the injury front ahead of Saturday's visit of Sheffield United, with goalkeeper Alisson Becker potentially in line for a return.

The Brazil international has missed the past three matches with a shoulder problem sustained in training but appears to be ahead of schedule in his recovery, having returned to light training this week.

Late fitness checks will also be made on midfield pair Thiago Alcantara and Naby Keita, as well as Matip, after all three missed the trip to Amsterdam.

Liverpool are likely to come up against former striker Rhian Brewster, whom they sold to Sheffield United on deadline day.

The highly rated 20-year-old was sold for £23.5 million ($30 million), with first-team opportunities limited following the arrival of Portugal international Diogo Jota.

"We all know him very well and that's the problem -- we know how good he is," said Klopp. "That's the situation.

"How always with a boy, especially like Rhian who is really our boy -- OK, maybe I have to say 'used to be our boy' - it means always I wish them really the nearly perfect Premier League season.

"If Rhian is on the pitch we know we should not let him finish at all because wherever he gets the ball he is a natural finisher and that's his biggest threat."

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