Arsenal midfielder Mesut Ozil is an injury concern for world champions Germany ahead of Saturday's Euro 2016 qualifier against Poland in Warsaw after being sent for a knee scan.
The 25-year-old Gunners' star has complained of pain in his left knee and flew to Munich on Wednesday morning to be treated by German Football Association (DFB) doctor Hans-Wilhelm Mueller-Wohlfahrt.
"There is a problem with his left knee. We can't say more at the moment, we'll have to see how it goes," said German Football Association (DFB) spokesman Jens Grittner.
Chelsea forward Andre Schuerrle also missed training on Wednesday with a muscular problem, but is expected to be fit.
"Things look good for Andre, he received some treatment on Tuesday, so it's normal that he sat out training the day after," said team manager Oliver Bierhoff.
Germany coach Joachim Loew is already missing several stars for the trip to Warsaw with Julian Draxler out with 'flu while captain Bastian Schweinsteiger, Sami Khedira, Benedikt Hoewedes, Marco Reus and Mario Gomez are injured.
Draxler is expected to join the squad once he recovers from illness and there are no plans to call up a replacement player.
"I don't believe that Jogi will call up a player, he doesn't like to do that once the squad is announced," said Bierhoff.
Germany also host the Republic of Ireland in a qualifier in Gelsenkirchen next Tuesday and Loew has targeted six points from their two games to give the Germans control of Group D after beating Scotland 2-1 in their opening match.
Bierhoff said Germany are rebuilding after established stars Philipp Lahm, Per Mertesacker and Miroslav Klose all retired since they won the World Cup title at Brazil 2014.
"We want to win both games and give ourselves a bit of a cushion in the qualifiers," added Bierhoff.
"It's going to be a tough October with two difficult games.
"We have to introduce several new players into the squad because of injuries and a few retirements.
"The team will have a different look to how it was two months ago."
With Schweinsteiger injured, Germany will be captained by goalkeeper Manuel Neuer for the next two games.
"These are key games for us, it is important to keep playing well after the win over Scotland," said Neuer.
Loew is set to hand a first cap to Bayer Leverkusen attacking midfielder Karim Bellarabi, who has opted to play for Germany over Morocco, where his mother was born, on the back of several impressive displays in the Bundesliga.
Germany face minnows Gibraltar in Nuremberg on November 14 before playing European champions Spain in a friendly in Vigo four days later.