Jurgen Klopp revealed the extent of the injuries to Alisson, Jordan Henderson and Andy Robertson after Liverpool’s 1-0 victory over Ajax.
Alisson missed the key clash with 22-year-old Caoimhin Kelleher impressing in his absence.
And Klopp says the injury isn’t serious but admits the Brazilian will likely miss the game against Wolves at the weekend.
Klopp said: “Alisson doesn’t have COVID. He told us after the [Brighton] game he felt it after 60-70 minutes, his hamstring.
“He’s had a scan, a little one, but enough for today and probably another week.”
Curtis Jones’ goal was enough to secure Liverpool’s path into the last 16, but there were further injury concerns for Klopp, with respective ankle and back problems for Andy Robertson and Jordan Henderson.
But Klopp is hopeful both will be fit for their Premier League fixture on Sunday.
“Both played through so I would say we have now two days more than we had last week so I think (they are OK),” he said.
“Things like this show up the next day a little different but in the moment I am positive about it. That is a problem for the next few days but not tonight.”