Schweinsteiger was forced to come off against Ghana
Germany playmaker Bastian Schweinsteiger could miss the World Cup second-round match against England on Sunday because of a thigh problem.
Schweinsteiger, 25, suffered the injury during Germany's 1-0 victory over Ghana in Group D on Tuesday.
"The team doctor says the recovery time is short. We just hope he's fit to play because he's become a key player," said Germany assistant coach Hansi Flick.
Left-back Jerome Boateng is also struggling to overcome a calf injury.
"Jerome has a bit of a calf strain and for both (Boateng and Schweinsteiger) it might be a bit critical for them to be in the starting line-up on Sunday, but we are optimistic," Flick added.
The absence of Schweinsteiger would still be a big blow for Joachim Loew's team as he has been a key player for them in the absence of injured captain Michael Ballack.
Mesut Ozil, who has impressed for the Germans and scored the winner against Ghana, has been nursing a twisted ankle but is expected to be fit to face England.
"Ozil seems to have twisted his ankle but he is not in pain and I think we will get him fit for Sunday's game," said Flick.