Indeed, Klopp could have done with all the men and strength he can summon for a pivotal encounter at the Stade Velodrome. Dortmund need to at least match the result of SSC Napoli against Arsenal FC in the group's other encounter to book their place in the last 16 of the competition, and the coach certainly has a lot to contemplate.
"Emergencies make you more innovative," he said prior to departure, and options were bound to be swimming around his head during the 90-minute flight to Provence-Alpes-Côte d'Azur. Captain Sebastian Kehl, a midfielder by trade, could find himself partnering Sokratis Papastathopoulos in the heart of the back four, with the fit-again Lukas Piszczek and Erik Durm as full-backs; Kevin Großkreutz is an alternative.
Ideally, though, Dortmund can resolve their defensive issues by keeping the ball in the opposition half, and giving Robert Lewandowski the task of firing them through to the knockout stages. "We mustn't let our heads drop," said the Bundesliga's top goalscorer. "We need to give absolutely everything we've got. It's a crucial game for us, and I'm sure that we'll do it."
Attack, therefore, is likely to be Dortmund's best form of defence, with a lack of deep-lying players prompting Klopp into fielding his full complement of attacking talent. The rare sight of Henrikh Mkhitaryan, Pierre-Emerick Aubameyang, Marco Reus and Lewandowski on the field at the same time seems unavoidable.
In charge of their own destiny
With the stakes so high, though, Dortmund cannot rely on Arsenal doing them a favour in Naples. With that in mind, Klopp said: "We're travelling to Marseille to ensure we spend the winter in the Champions League." It is a matter of all or nothing for Dortmund, and time for the men to emerge from the boys.
Marseille: Mandanda - Fanni, Mendes, Diawara, Morel - Lemina, Imbula, Cheyrou - Thauvin, Gignac, J. Ayew
Dortmund: Weidenfeller - Piszczek, Großkreutz, Sokratis, Durm - Mkhitaryan, Kehl - Blaszczykowski, Reus, Aubameyang - Lewandowski