Mohamed Salah limped off towards the end of Egypt's 4-1 friendly win over Swaziland with a "muscle strain".
Prior to the injury, Salah scored directly from a corner in the Africa Cup of Nations qualifier.
Salah has struggled to hit the heights of last season during the current campaign with Liverpool, but Jurgen Klopp will be anxious to see his star man hobble off.
Liverpool have a nice spell on paper when they resume club action, with games against Huddersfield, Crvena Zvezda and Cardiff City in October.
Egypt assistant Hany Ramzy moved to ease fears over the 26-year-old's fitness post-match by insisting it was "not a big injury".
Egypt's assistant coach Hany Ramzy did not believe the issue to be serious, telling BeIn Sports: "The initial diagnosis of the Egypt national team medical staff is that Salah suffered a muscular injury, he will be examined to determine the details, but in my opinion it is not risky".
Liverpool's next game is away to Huddersfield on October 20 when the Premier League resumes after the worldwide break.
The win takes Egypt provisionally up to second in AFCON qualifying Group J, having taken six points from their opening three matches.