Sadio Mane was injured during Bayern Munich's match against Werder Bremen at the Allianz Arena.
The 30-year-old looked to injure his knee early in the encounter, with only 21 minutes played and was evaluated by medical personnel before being replaced by Leroy Sane.
The injury concern comes only 13 days before Senegal's World Cup campaign kicks off against the Netherlands.
Senegal's Mane featured in each game this year and converted the winning penalty to defeat Egypt in the African Cup of Nations final.
He moved to Bayern from Liverpool in June in a contract that, depending on performance-related bonuses, could total 41 million euros ($41.3 million).
In Mane's absence, league leaders Bayern increased their advantage to 4-1 before halftime.
Bayern added two more goals from Mathys Tel and Serge Gnabry to make it 6-1.
According to reports in Germany, the Bavarians will run several tests on Sadio Mane on Wednesday morning to know the extent of the injury.