Liverpool manager Jurgen Klopp has Alisson is out for up to two weeks with a hamstring injury.
The Brazilian goalkeeper joins teammates James MilnerTrent Alexander-Arnold, Naby Keita, Xherdan Shaqiri, Joe Gomez, Virgil van Dijk and Thiago Alcantara on the sidelines.
Asked why Alisson was not in the Liverpool side to face Ajax on Tuesday, Klopp said: "It is not Covid.
"That is something we have to mention when it is not the case, and it is not the case. He told us after the game [against Brighton] he felt his hamstring in the 60th or 70th minute.
"A little one but enough for today and probably for another week, we will have to wait and see. I have never heard of a hamstring that is only four or five days so it will be 10 to 14 days, I think."