That would have ruled Salah out of Egypt's final AFCON group-stage match and a last-16 fixture, had the Pharaohs made it through to the knockout stages.
Jurgen Klopp then suggested that Salah would return to Merseyside for treatment on the injury and that has now been reiterated by Ramy Abbas, who revealed that the problem was more significant than initially suggested.
“The injury is more serious than first thought," Salah's agent posted on X.
"He will be out for 21-28 days. His best chance at participating in the current AFCON is by undergoing intensive rehabilitation in the UK and rejoining the team as soon as he is fit."
The semi-finals of the tournament will take place on February 7, with the final four days later, and Salah now faces a race to play again for his country, assuming they are able to make a deep run in his absence.
The Liverpool star will travel back to Merseyside following Egypt's final group-stage match on Monday night against
A statement from the Egypt Football Associated read: "Salah will attend the Cape Verde game and travel to England afterwards.
"After carrying out additional examinations in the last hours and after communication between the medical department of the national team and his counterpart at Liverpool, it has been confirmed that the player will return to England to complete his treatment, hoping to catch him in the semi-finals of the CAF Nations Cup in case of qualification."