The Frenchman visited a hospital on Thursday afternoon to have a hematoma removed from his buttocks, which was pressing a nerve, and will consequently be out of action for a while.
The 30-year-old will remain in the clinic until Sunday and is scheduled to undergo further examination on Monday before Bayern makes a decision on his recovery process.
"I hope that Franck will resume regular training again as soon as possible," commented Bayern coach Pep Guardiola on the winger's absence at a press conference.
Ribery has been a key figure at Bayern so far this season, scoring seven goals in 14 Bundesliga appearances, while creating nine more.
The reigning Bundesliga champion currently sits atop of the league table, holding a 13-point lead over second-placed Bayer Leverkusen.