Sami Khedira could miss Germany's World Cup qualifier at home to Sweden on Tuesday after suffering a muscle injury during the 6-1 demolition of Ireland in Dublin on Friday.
Germany coach Joachim Low told reporters Real Madrid midfielder Khedira was still receiving treatment but may not recover in time to play.
"We have just one problem at the moment - the question of Sami Khedira," Low said. "We do not know 100% whether Sami will be fit to play as he was treated today and will continue to be treated this evening."
Germany have taken a maximum nine points from their opening three Group C games, and welcome back captain Philipp Lahm after a one-match ban.
"Defensively we did it very well [against Ireland]," Low said. "But obviously Philipp Lahm will return to the team after the end of his suspension."
Lahm is expected to play on the right in place of his Bayern Munich colleague Jerome Boateng, with Marcel Schmelzer at left-back.
Last week, Low came under fire in the German media for criticising Schmelzer. The coach had said he had no option but to play the 24-year-old Borussia Dortmund defender despite his poor international form.
Schmelzer has been in fine form for his club, with his Champions League performances against Manchester City and Ajax catching the eye.
Low, however, criticised him after the recent World Cup qualifying win against Austria, saying: "We don't have a lot of options - thus we have to continue to work with him. I hope he gets better at international level."
But the contrite coach said: "My choice of words was very, very unfortunate. That was not meant to come out that way. The choice of words was out of order. I have discussed it with him."