Liverpool boss Jurgen Klopp is adamant Alisson will play again this season.
However, he admits the goalkeeper's 'muscle injury' is proving a concern.
"There is no real timescale on it, but it is a proper muscle injury," Klopp said. "Different players recover differently. That is it pretty much. It is not a short one.
"It is not that he will be in contention for next week or something like that. We have to wait a few more weeks, definitely, for him.
"He is working in the gym, not on the pitch, it is a rather serious one but not a season-ending injury."