Mane was substituted early in Bayern's home match against Werder Bremen with an injury to his leg, replaced by former Man City winger Leroy Sane in the 20th minute.
The former Liverpool player went directly down the tunnel for further treatment.
The injury gave rise to fears that the two-time African Footballer of the Year may not be fit for the start of Senegal's World Cup campaign.
Speaking to reporters after the game, Topmoeller allayed fears Mane may miss the showpiece event, saying an early diagnosis indicated a nerve injury.
"He copped a knock on a nerve (in the leg). It seems to be not too bad."
Senegal face the Netherlands in their opener on November 21st 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.
