Salah was forced off midway through the first half of Liverpool’s 3-1 defeat to Real Madrid on Saturday after colliding with Sergio Ramos.
The 25-year-old, who has scored 44 goals in 52 appearances this season, now faces a race against time to prove his fitness ahead of the World Cup, which gets underway on June 14.
Egypt’s Football Association confirmed Salah will head to Spain for a rehabilitation programme following consultation with Liverpool.
According to an EFA statement, Salah will be accompanied by Liverpool’s medical staff “for the duration of the treatment period”, having “started his rehabilitation on Sunday”.
Egypt take on Uruguay in their opening World Cup match on June 15 before facing hosts Russia and Saudi Arabia in their remaining Group A games.
“It was a very tough night, but I’m a fighter,” he said after the defeat to Real Madrid. “Despite the odds, I’m confident that I’ll be in Russia to make you all proud. Your love and support will give me the strength I need.”