“Mats Hummels will probably not be able to play. He somehow dislodged a vertebra in his neck yesterday and has not improved,” Low said at Friday’s pre-game press conference.
“There is still time, but when things like that happen you don’t generally improve overnight.”
Chelsea’s Antonio Rudiger would be the likely replacement for Hummels alongside Jerome Boateng in the heart of the German defence.
The defending world champions come into Saturday’s game in Sochi with their hopes of reaching the last 16 hanging by a thread after losing their opening match 1-0 against Mexico.
A defeat on Saturday could eliminate Low’s side, depending on the result of the day’s other Group F game between Mexico and South Korea.