Borussia Dortmund defender will miss the DFL-Supercup meeting with former club Bayern Munich after sustaining an injury in training.
The German centre-back completed a sensational return back to BVB this summer for £27m after reportedly being told by Bayern boss Niko Kovac that he would have to settle for a rotation role.
With Bayern signing centre backs Benjamin Pavard and Lucas Hernandez for over a €100m, Hummels decided to leave in search for consistent playing time.
Die Roten are set to meet Die Schwarzgelben in the DFL-Supercup (Germany's equivalent to the Community Shield) yet Hummels will reportedly miss out as per Sven Westerschulze, a reporter for Bild.
Despite Bayern winning both the Bundesliga and DFB Pokal, Dortmund will be their opponents as the second place in the Bundesliga will be in the Supercup if a club has completed the domestic double.
Both clubs have met in the rebranded version of the Supercup five times out of a possible eight, with Bayern winning three and Die Borussen winning the other two. The reigning Supercup holders have come out on top the last two times against them, therefore Dortmund will look for some revenge and start the season with some momentum.
With experienced defender Hummels out, Dortmund will have only three centre backs to choose from as French Under-20 international Dan-Axel Zagadou is also set to miss the game. That only leaves Manuel Akanji, Omer Toprak and Leonardo Balerdi as options for Lucien Favre.
Der BVB will also be without new signings Julian Brandt and Thorgan Hazard, while Bayern have Serge Gnabry and Lucas Hernandez missing. Kingsley Coman is reportedly set to feature after training with the squad despite suffering a bruised knee in their last friendly against Spurs.
Even though Hummels' return would have added an extra caveat to the game, the Supercup fixture will certainly still be an exciting preview of the title race that will unfold this upcoming season.