Arne Slot fears the hamstring injury Alisson picked up in Liverpool's 1-0 win at Crystal Palace will rule him out for a "few weeks."
Liverpool secured the points after Diogo Jota scored in the ninth minute, but will face concerns over both Alisson and midfielder Alexis Mac Allister, who was replaced at half-time after feeling a problem in his groin.
Alisson missed their 3-0 win against AFC Bournemouth through injury, and he was forced off in the 79th minute of their trip to Selhurst Park after injuring his hamstring.
Third-choice goalkeeper Vitězslav Jaroš replaced Alisson and made his Liverpool debut after usual second-choice keeper Caoimhín Kelleher was absent through illness for their match with Palace.
The 32-year-old was later ruled out of Brazil's upcoming World Cup qualifiers, away at Chile on Oct. 10 and at home to Peru five days later. Liverpool face a brutal run of matches after the international break, and Slot fears Alisson will miss some club action, with Liverpool hosting Chelsea on Oct. 20 and then travelling to RB Leipzig on Oct. 23 in the Champions League.
"If a player walks off like he does, that normally means he's not in the Brazil squad, and I don't expect him to be in the first game afterwards," Slot said. "It'll take a few weeks I assume."
With Alisson potentially absent, Slot will turn to Kelleher to fill his boots, despite Jaroš' cameo at the end of their sixth win in seven Premier League matches this term.
"Alisson is our clear No. 1, the best goalkeeper in the world so it's a blow when he gets injured for himself and the team," Slot said.
"We have a second option that's already good. Caoimhín has already shown that, which is why Caoimhín is the No. 2 and the last time, Alisson was injured, I played Caoimhín. He did really well, it's pleasing to see that our third goalkeeper can have an impact on results as Caoimhín was ill yesterday and today."
Argentina midfielder Mac Allister was substituted at half-time.
"Yeah he went off because of an injury, how bad it is, that's difficult for me to judge in this moment," Slot said of Mac Allister. "He could've continued playing like you saw because it didn't happen one second before half-time.
"He said he didn't think it was right to continue playing as he could make it worse. Now what is the exact situation? Can he go to Argentina? Can he play over there? That's difficult for me to tell you right now."
The win was Slot's ninth win in his first 10 matches as Liverpool head coach. That's the best record out of any Liverpool manager in the club's history and while he is honoured by such a statistic, he doesn't want that to define his tenure.
"It's quite special when you know how many great managers Liverpool have had," Slot said. "[But] don't only remember me for this, we are hoping to do more special things. I also had the luck of inheriting a good squad and good staff to continue getting good results."
For Crystal Palace, they are still waiting on their first win of the season, with three draws and four defeats so far this term. Their manager Oliver Glasner was left angered by the referee missing what he felt was a clear penalty in the second half when Marc Guéhi was hauled down in the penalty box by Virgil van Dijk.
"We should've got the clear penalty, Marc Guehi was held with two hands," Glasner said.
But despite the defeat, Glasner was pleased with aspects of Palace's showing. "The performance in the second half was good," Glasner said.
"We made a great start in the first half, but you could see the quality of Liverpool ... how they play, making the runs in behind, this is why they're the best team in England. They deserved the lead, but the reaction in the second half encourages all of us. We created chances and we had enough chances to score. The second half performance was the best of the season, and it gives me a lot of confidence."