Senegal forward Sadio Mane was substituted early in Bayern Munich's home match against Werder Bremen on Tuesday with an apparent knee injury.
Mane picked up the injury in the 15th minute and required treatment, before being replaced by former Manchester City winger Leroy Sane five minutes later.
The former Liverpool player went directly down the tunnel for further treatment.
The two-time African Footballer of the Year will be desperate to be fit for the start of Senegal's World Cup campaign.
Senegal face the Netherlands in their opener on November 21 in Qatar, before further Group A matches against the hosts and Ecuador.
Mane's penalty in the shootout win over Egypt helped Senegal win their first-ever Africa Cup of Nations title earlier this year.