The Gunners have it all to do at Emirates Stadium after enduring a 5-1 humbling in the first leg of the last-16 encounter.
Bayern may already have one foot in the quarter-finals, but they will need to maintain their concentration throughout in north London.
Hummels was certainly found wanting in that department as Bayern prepared to depart for England, with the World Cup winner enduring a moment to forget while preparing to get on the club bus.
Läuft bei mir pic.twitter.com/jgyMhud1C6— Mats Hummels (@matshummels) March 6, 2017
While Hummels was forced to hang his head in shame, those around him delighted in seeing a colleague lighten the mood.
Thomas Muller was particularly pleased to see a club and international team-mate cover himself in a hot beverage, with little sympathy offered by those who witnessed the incident.