Manager Arne Slot delivered the frustrating injury update following their 1-0 defeat against Turkish side Galatasaray.
Victor Osimhen scored the winning goal for his team from the penalty spot after a foul by Dominik Szoboszlai in the box.
The goalkeeper then got injured in the second half after saving Osimhen’s effort, denying the Nigerian his second goal of the game.
Slot addresses Alisson’s injury
Slot has addressed concerns over goalkeeper Alisson, who was forced off with an injury during Tuesday night's loss to Galatasaray.
He confirmed that Alisson will be unavailable for this weekend's Premier League fixture, though the full extent of the injury remains unclear.
"It is never a positive sign when a player has to go off like this," Slot said, as reported by the Sun. "When my player is on the floor, nine out of ten times I fear the worst."
"And by the worst, I mean that he cannot continue, and that is what happened with Alisson. Normally, he will not be able to play on Saturday, that's 99.9 percent. I have already said 100 percent, but let’s make it 99.9."
Alisson's injury could open the door for Georgian backup keeper Giorgi Mamardashvili to make his Premier League debut.
The towering shot-stopper joined from Valencia in the summer but has only featured once so far, in Liverpool's 3-1 Carabao Cup victory over Southampton.
The Reds will be desperate to regain the momentum that took them to the top of the league, having lost their last two matches in all competitions.