Salah, 25, suffered a shoulder injury during his side's 3-1 loss to Real Madrid in the Champions League final on Saturday.
"I have contacted the good son of Egypt and my son, Mohamed Salah, to reassure him after his injury," the president wrote on Twitter.
"As I expected, I found him a hero who is stronger than the injury and is excited to continue the path of tournament and excellence."
He added: "I told him he became an Egyptian icon, sending an honour and pride.
"I pray for Allah, like a father to his son, for him to be well soon."
تواصلت مع إبن مصر البار وإبنى محمد صلاح للإطمئنان عليه بعد إصابته .. وكما توقعت وجدته بطلاً أقوى من الإصابة ومتحمساً لإستكمال مسيرة البطولة والتميز ، وقد أكدت له أنه أصبح رمزاً مصرياً يبعث على الفخر والإعتزاز وأننى أدعو الله له دعاء الأب لإبنه بأن يحفظه ويتم شفائه على خير.— Abdelfattah Elsisi (@AlsisiOfficial) May 27, 2018
Egypt begin their World Cup campaign against Uruguay on June 15.