Mane is the focus of a Senegal team which won its first African Cup of Nations title this year and is rated by many as the best African side to ever go to a World Cup. It has realistic hopes of making the quarterfinals and may be Africa's best chance yet of making history and reaching the last four at a World Cup.
The 30-year-old Mane has been vital for Senegal, scoring the penalty that won the African Cup title in a shootout against Egypt in February. A month later, he also netted the winning penalty in another shootout that clinched Senegal a place at the World Cup in Qatar in a playoff, again beating Egypt. He recently became his country's all-time leading scorer and finished second in this year's Ballon d'Or behind Real Madrid's Karim Benzema.
News of Mane's injury in Germany put his West African home nation on tenterhooks. Even Senegal President Macky Sall sent out a tweet hoping for Mane's recovery in time for the World Cup.
Senegal will play host Qatar, the Netherlands and Ecuador in Group A and Cisse said his squad would continue to prepare as they had planned, despite the situation with Mane.
"For the moment, there is no question of changing anything," Cisse said.
World Cup rules allow teams to replace an injured player up to a day before the team's opening game, meaning Senegal still has the option of bringing in another player later on if Mane doesn't recover in time. That would still be a major blow for Senegalese hopes and the World Cup itself.
At 30, Mane is probably at his peak right now and may not get another chance at the World Cup.
Senegal's World Cup squad
Goalkeepers: Seny Dieng (QPR), Alfred Gomis Rennes), Edouard Mendy (Chelsea)
Defenders: Kalidou Koulibaly (Chelsea), Ismail Jakobs )Monaco), Pape Abou Cisse (Olympiacos), Abdou Diallo (RB Leipzig), Youssouf Sabaly (Real Betis),Formose Mendy (Amiens), Fode Ballo Toure (Milan)
Midfielders: Pape Matar Sarr (Tottenham), Pape Gueye (Marseille), Idrissa Gana Gueye (Everton), Nampalys Mendy (Leicester), Moustapha Name (Pafos), Mamadou Loum (Reading), Cheikhou Kouyate (Crystal Palace), Krepin Diatta (Monaco), Pathe Ciss (Rayo Vallecano)Forwards: Sadio Mane (Bayern Munich), Ismaila Sarr (Watford), Bamba Dieng (Marseille), Nicolas Jackson (Villareal), Ilman Ndiaye (Sheffield United), Boulave Dia (Salernitana), Famara Diedhiou (Alanyaspor)