Manchester United midfielder Bastian Schweinsteiger will miss Germany's friendly against England on Saturday after injuring his knee.
Germany coach Joachim Loew said Schweinsteiger's medial ligament injury did not "look very positive" and the 31-year-old may have suffered a tear.
"I am not able to give an exact timescale as to how long he will be out," Loew added.
Schweinsteiger will definitely also miss Tuesday's friendly against Italy.
He will have a scan on the joint in Munich to assess if it is a repeat of the tear he suffered in Manchester United's FA Cup third-round win over Sheffield United in January.
That injury sidelined the former Bayern Munich player for two months. He made his return in United's 2-0 Europa League defeat at Liverpool on 10 March.
Manchester United are a point and two places off the Premier League's top four with eight matches remaining. They also have an FA Cup quarter-final replay against West Ham on April 13.