Liverpool manager Jurgen Klopp has confirmed Alisson is facing a significant spell on the sidelines.
The Brazilian was omitted from Sunday's loss to Aston Villa after suffering an injury to training.
And Klopp admits his star goalkeeper will likely miss the Merseyside derby which will take place after the international break on October 17.
"Yesterday an incident in training, very unlucky – two players clash with each other, one gets up, one doesn't," said Klopp. "The one who didn't get up was Ali.
"So, after the first few things, we don't know 100%. But he cannot play today.
"We have to do further assessment; but he's injured, let me say it like this. Now we hope it will go really quickly.
"It's an international break, I'm pretty sure after that he will not be ready. Then we have to see week by week."
