Mane is expected to face six weeks on the sidelines after picking up the injury during Senegal's World Cup qualifier with Cape Verde Islands on Saturday, ruling him out of this weekend's crunch match with Manchester United.
Salah is keen to prove that Liverpool can cope without the 25-year-old, though, and is eyeing victory over their fierce rivals at Anfield on Saturday.
"I texted him when he was at the national and then when he came back. He told me then he was injured so that's bad news for everyone," Salah told reporters.
"But that's football and anything can happen. Now we have to focus on the game and keep moving forward. It's a big game on Saturday, everyone in the world will watch the game. It's a big game for us too because we have to keep fighting and improve our results. I hope we can get the win.
"We always fight in each game, but this game is a big game and can make a difference for us. We have to improve our place in the table. We have to fight and try to win the game."
Salah has scored four goals in seven Premier League appearances for Liverpool so far this season.