Liverpool head coach Jurgen Klopp has admitted that Fabinho is set to miss some time after hobbling off in Tuesday's Champions League clash with Midtjylland.
The Brazilian was forced out with an apparent hamstring injury after just under half an hour and was replaced by Rhys Williams.
Second-half goals from Diogo Jota and Mohamed Salah would give the Reds a 2-0 win on the night but it could prove to be a costly victory for Klopp's men.
With Virgil van Dijk out long term, Fabinho has been filling in at centre-back but Liverpool's depth in defence will now be severely tested with the former Monaco man also set to miss time.
Klopp told beIN SPORTS: "We have to wait for the scan obviously but you know these times when somebody is going off with a muscle problem, then it's really rare that the doctor calls me the next morning and says: 'False alarm, all fine, he can go again.'
"So it's now only about how long. That's all. And nowadays a week means three games, 10 days means four games, 14 days means seven games and all these kinds of things.
"So that's how it is. Yeah, absolutely not cool but that's the situation."
Speaking to BT Sport, Klopp admitted that his side would now be forced to navigate a difficult period due to their injury crisis at the back.
"It was a tough night," Klopp said. "It's a bit like in a marriage, there are good and bad times. It's not a bad time but it's a tricky time.
"100 per cent we have to stick together and fight harder and that's what the boys did tonight. Losing Fabinho in the first half, Rhys Williams he's only 19 years old and I think he's played more Champions League games than Premier League games - that's rare.
"We're doing really well but it's a shock for a team because now we have to sort that injury."
On Fabinho's injury, Klopp added: "Exactly the last thing we needed. I don't know, he felt his hamstring so that's not good. He didn't feel it that much. He said he could've played on but not sprinting so that doesn't help. We will see, we will have to do a scan and see but clearly it's not good."