Midfielder Bastian Schweinsteiger will miss Germany's final warm-up match ahead of Euro 2012 against Israel on Thursday night through injury and remains a doubt for the championships.
The Bayern Munich player, who is the vice-captain of the national team, was unable to train again on Wednesday due to a calf problem.
Captain Philipp Lahm admitted the injury was a concern.
"If a player cannot training then clearly he has a bad knock," he said. "He would love to train and play, as much as us we all do, so of course it is serious.
"Bastian is important both at Bayern Munich and in the national team.
"Of course it would hurt (if he doesn't recover). We all want experienced players fit from the start of a tournament, but if not, we would not be too worried as we know we have strength in depth."
Germany, who were beaten 5-3 by Switzerland last weekend, have just 10 days after Thursday's friendly in Leipzig to get Schweinsteiger fit, but general manager Oliver Bierhoff denied they are taking a risk by naming him in their 23-man squad.
"We are fully confident that it will work out," he told a press conference in southern France. "We are sure he will be ready for the first group game.
"It is not the same as with Michael Ballack (in 2008). He had a recurring problem so he knew how to cope with it. This is just a one-off knock and we all hope he recovers."
Schweinsteiger's absence is set to pave with way for Bayern team-mate Toni Kroos to partner Sami Khedira in the defensive midfield.
Further experiments can be expected from coach Joachim Low and Lahm claimed the result on Thursday night will not be the most important factor.
"(This) is our last warm-up game and we must not expect too much from such tests," he said.
"We want to win, play a good game and gain self-confidence, but then we have a week to train even more. Then we will be well prepared for the Euros."
Lahm also echoed the words of Low, who has banned the word 'final' from his players' vocabulary.
"We have always done well in recent years to think on a game-by-game basis," said the Bayern full-back.
"We have the quality to go a long way, but you need to make a good start and we are playing Portugal to begin with, and if we win, it would be good in a very tough group.
"We cannot think of the quarter-finals, the semis or the final. We have got to get through the group phase and we all know how difficult that is."
Germany are one of the favourites for the tournament, even if Lahm has had a recent bad experience of such a tag.
The Champions League final defeat to Chelsea on penalties is proof nothing can be taken for granted.
"That's the way sport is, you cannot always win and there are defeats," he said.
"We have quality and we can be successful in coming years too, but there is still not a guarantee that you win.
"That's sport. You cannot always be first."