The Dutchman opened the scoring before being stretchered off in the Bundesliga champions' DFB Pokal round of 16 victory over Augsburg
Robben was substituted after only 16 minutes of Bayern's DFB Pokal round of 16 encounter with Augsburg following a nasty collision with the hosts' goalkeeper Marwin Hitz, leaving him with a gash on his right knee.
The winger had to be stretchered off as he was unable to walk off the park and was replaced by Thomas Muller.
There is no indication of how long Robben could be sidelined but the Bavarians' sporting director Matthias Sammer says the 29-year-old was taken to hospital to cleanse the wound.
The injury put a dampener on what was a successful night for Pep Guardiola's men as they overcame Augsburg 2-0 to seal their place in the next round.
Robben had initially given Bayern the lead after only four minutes before his night came to an abrupt end when he collided with Hitz.
And the Oranje star's replacement Muller scored the clincher on 78 minutes after good work by Jerome Boateng.