Liverpool were already 3-0 up when Adrian was called upon to replace Alisson, who managed to leave the field without a stretcher despite looking in a great deal of pain.
"I don't want to make now [an] exact prognosis on when he will be back but it will not tomorrow for sure, so now then we have to see".
Lonergan is expected to be on the bench for the Super Cup match against Chelsea in Istanbul on Wednesday.
Lonergan had remained with the Liverpool camp for the rest of their pre-season trips to Edinburgh as well as the training camp in Evian and also travelled with the team for the Reds Community Shield defeat to Manchester City.
Asked if Lonergan will be on the bench against Chelsea, Klopp said: "I think so". "I didn't speak to John [Achterberg, Liverpool goalkeeping coach] yet about that".
"We have to see how that works but that's then how we cover that situation".
"He was maybe louder than I was at half time, he is obviously quick in mind and helped us a lot and can be really proud", he added.
Alisson's loss for an extended period would be a big blow to the club he joined from Roma previous year.
Alisson's injury: Five things to know......
But, aware of the nerves his players might be feeling ahead of the game in Kiev, Wijnaldum has revealed how Klopp insantly lifted the pressure by arriving for a team meeting wearing Ronaldo-branded boxers.
Fast forward to the opening day of the 2019/20 season and Liverpool started against Norwich City with Trent Alexander-Arnold, Virgil van Dijk, Joe Gomez and Andy Robertson. If Alisson is set to miss 6-8 weeks of football, he will most likely not feature in the games against both those London clubs. I don't think he's won a lot in his life, so I'm really happy for him.