Salah left the field in tears in the 30th minute unable to continue the game, with doubts placed on his World Cup participation.
"Through follow ups on the phone with the national team's delegation in Italy...the officials at Liverpool said an X-ray on Salah's shoulder" showed the injury to be in the ligaments, the Egyptian Football Associated said on Twitter on Saturday.
A three-week absence would keep Salah out of action until June 19 while four weeks would see the forward sidelined until June 26, the day after Egypt's last group-stage game.
Egyptians consider Salah a symbol of national pride and hope after he scored the late victor from a penalty shot during the penultimate game of the 2018 World Cup qualifications against Congo, ending Egypt's 28-year World Cup drought.More news: Chris Evert criticizes French Open for not seeding Serena Williams
Many football fans around the world have signed an online petition asking Real Madrid's Sergio Ramos to be punished for "intentionally" injuring Liverpool forward Mohamed Salah.
"I didn't say anything because a lot of people already went to him and sometimes you don't like it when too many people come to you".
The Egyptian footballer has embarked on a race against time to prepare for the Russia-hosted major football event due to kick off in two weeks.
"We are going to do double session every day and we will try to reduce the recovery period".