The 30-year-old was withdrawn with an apparent knee problem after only 21 minutes of the encounter and manager Julian Nagelsmann did not provide much clue after the game as to how significant the issue was.
“I didn’t see him after the game, I hope it’s not a big injury. But I don’t know at the moment. We’ll see tomorrow and then give an update,” he said.
Senegal’s first game is just 13 days away, as they face Netherlands in Group A before also playing hosts Qatar and Ecuador.
Mane is a key player for Senegal, having won 92 caps and scored 34 goals - the all-time record holder in the latter category and ranked third for appearances.
He scored the penalty which sealed the Africa Cup of Nations for his country earlier this year, before also scoring in the Lions of Teranga’s CAF qualifier shootout which sent Senegal to Qatar.
Mane now joins a list of players anxiously hoping for good news over injuries sustained in the run-up to the tournament, which includes Son Heung-min, Kyle Walker and Ronald Araujo.
His replacement, Sane, had been an injury doubt himself for Germany after injuring a thigh muscle in mid-October, but he marked his second appearance off the bench in a week with an assist in Bayern’s rout.
Serge Gnabry hit a hattrick in the game, with Bayern now going four points clear at the top after Union Berlin’s weekend defeat to Bayer Leverkusen.
Union, now third, and second-placed Freiburg are both in action on Wednesday. The Bundesliga has one more weekend round of matches to play through before the break for the World Cup finals and does not resume until mid-January.