Germany skipper Michael Ballack admitted that the host's winning chances at the World Cup are not that big due to the lack of stability and experience of a young squad.
"We have players that have been on the pitch only sporadically with their club teams. We don't have the choice of players we had in the 1990 World Cup or in the 1996 European Championship," Ballack said in an interview with a local newspaper on Wednesday.
"As a result the team makes mistakes and is not fixed. For that reason I think there is a little uncertainty as we head into the tournament," he added.
"The results and performance in the run-up to the World Cup show that this team is not so stable."
Germany meet tournament underdogs Costa Rica on Friday in Munich in the curtain-raiser. Costa Rica had some poor performance in recent warm-up matches but the German side also got bittersweet results.
They beat Colombia 3-0 in their last World Cup warm-up match but ground out a draw against Japan last week and were pounced 4-1 by Italy back in March.
Ballack, who is suffering from a calf injury that prevented him from training on Tuesday afternoon, said the team needed to be careful about moving forwards too quickly to leave the defence exposed.
"We need to be clear that we can't all have an offensive mindset," Ballack said.
Germany are drawn with Costa Rica, Poland and Ecuador in Group A.