Liverpool manager Jurgen Klopp suffered another injury blow with Fabinho joining Virgil van Dijk on the sidelines after picking up a hamstring injury in Tuesday's Champions League win over Midtjylland.
Midfielder Fabinho has been filling in for Van Dijk in the centre of defence since the Dutchman suffered a serious knee injury in the Merseyside derby against Everton.
"It's exactly the last thing we needed," Klopp said, after Fabinho limped off in the first-half of the 2-0 win.
"I know he felt a hamstring, and that's not good. He said he could have played on but no sprints, which doesn't help. We will see, we will know more after a scan but clearly it isn't good," he added.
"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," Klopp added. "We're doing really well but its a shock for a team because now we have to sort that injury."
Klopp accepted that the Premier League champions were in a difficult period.
"It was a tough night. 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% we have to stick together and fight harder and that's what the boys did tonight," he said.
Meanwhile, Liverpool goalkeeper Alisson believes Van Dijk will be out until next season.
Asked about his absence, Alisson told Esporte Interativo: "He's important for the team, for all of us, for me too. Unfortunately, we ended up losing Virgil probably for the rest of the competition. We don't know the set dates yet, anything can happen, but that's likely, that's what we have in hand."
Alisson returned to play at the weekend after being sidelined with a shoulder injury for three weeks.
"To be back, to be one more part within the squad, within the team to be able to help, I'm feeling very happy," he said. "I believe it also gives confidence to the team. Everyone we can have available now, from now on, it's important to fight for our goals, which are big.
"It was only three weeks, to me it felt like three months. Being back, being able to help the team... For a player, being left out is the worst part of football, but it is part of the package, we are subject to injuries, nobody wants it, but we're subject. But I tried to recover in the best way and in the quickest possible way to be back and help my teammates and getting back to the Champions League already."