Salah was forced off in the 88th minute of Egypt’s 4-1 win over eSwatini - the country formerly known as Swaziland - in Cairo on Friday evening.
The 26-year-old had ended his personal goal drought in the first half by scoring direct from a corner to put the hosts four goals ahead but limped off late on.
After the game, Egypt assistant manager Hany Ramzy played down fears over the injury, telling beIN SPORTS: "The primary diagnosis confirms it's just a strain and no muscle rupture is apparent.
"But the player will need to undergo scans to determine the full extent of the injury and the time needed to heal.
"It's nothing major, we'll do the best we can to help him recover. We hope he's fit as soon as possible."
Salah withdrew from the squad ahead of Tuesday’s scheduled return Africa Cup of Nations qualifying fixture in order to travel back to Merseyside yesterday.
The forward will be joined at Melwood by Netherlands captain Van Dijk, who scored in a 3-0 Uefa Nations League win over Germany on Saturday.
Photo: AFP/Getty Images
The 27-year-old has been playing through a rib injury of late and will miss this week’s friendly meeting with Belgium in order to undergo further treatment.
Liverpool resume their Premier League campaign at Huddersfield Town on Saturday.