Salah sustained the knock during Liverpool's 3-1 defeat to Real Madrid on Saturday, which raised concerns over his potential participation in the upcoming tournament in Russia.
Reds boss Jurgen Klopp declared the injury as 'really serious' in the post-match interview in Kiev but the Egyptian FA have since confirmed that his absence will 'not exceed three weeks'.
"After the meeting of Abu Rida and the doctor of the national team in Spain today, the Football Association reaffirms Salah in the World Cup, God willing, will not exceed the absence of three weeks," the Pharoes tweeted yesterday.
According to the X-ray results, the PFA Player of the Year suffered a sprain in the shoulder ligaments and will be a doubt for their first fixture against on 15 June.
Egypt were drawn in Group A with hosts Russia, Saudi Arabia and Uruguay, with whom they open their campaign against.