Marcell Jansen has been ruled out of Germany's upcoming World Cup qualifiers with Russia and Wales after picking up a thigh strain at the weekend.
The Hamburg defender is expected to be out for over a fortnight and may not be fit for their next Bundesliga fixture either.
"The availability of Marcell Jansen against Schalke in two weeks is questionable," said Hamburg's team doctor Oliver Dierk.
The 22-year-old will still join up with the national team in Dusseldorf on Tuesday, where he will receive treatment from the national team doctors, but will be unable to figure for Joachim Low's side.
Jansen tore muscle fibres in his left thigh during his side's 2-1 win over Energie Cottbus on Sunday.