Marco Reus and Omer Toprak are unlikely to be fit to play for Borussia Dortmund against Bayern Munich on Saturday, according to head coach Peter Stoger.
Germany forward Reus missed the 1-0 Bundesliga win over Hannover before the international break due to an adductor injury.
Defender Toprak is battling a thigh problem, and Dortmund may have to make do without the pair when they travel to face runaway leaders Bayern in Der Klassiker at Allianz Arena.
"I don't think it'll be sorted by the weekend," the coach was quoted as saying by the Bundesliga website.
"If they keep progressing as they are, it could happen that they take part in training at the end of the week. Then comes the question of whether it's enough for the Bayern game."
Dortmund are third in the table, one point behind second-placed Schalke but 18 back from Bayern.