The Brazilian goalkeeper is sidelined due to a hamstring injury, meaning Caoimhin Kelleher makes his European debut for the Reds.
Speaking to BT Sport pre-match, Klopp also admitted Alisson was likely to miss the weekend's Premier League match with Wolverhampton Wanderers.
The boss said: "So it's not COVID, I think it's something we have to mention when it's not the case – and it's not the case.
“He told us after the game that he felt in the 60, 70th minute of the last game his hamstring. [We] did a scan, it's a little one but enough for today and probably for another week.
“We don't know exactly, we have to wait and I've never heard about a hamstring is only four or five days, so 10 to 14 days I think.
“Then we had to make the decision: Queev or Adrian. And Queev, I know him pretty much five years, four years for sure – I'm not sure when he came to the first team, training with us and stuff like this.
“He's just improving and improving and improving and he's a football-playing goalie, good shot-stopper, which is obviously the most important thing. My job is to make decisions and I did that.”