"It seems that Michael Ballack can not play against Costa Rica," Klinsmann said at a press conference Thursday.

The Chelsea midfielder could not complete Wednesday's training session through a persisting calf injury.

"He only trained for 30 minutes on Wednesday and then had to pull out," said Klinsmann.

Ballack had suffered a slight strain to his right calf during Germany's 3-0 win over Colombia in an international friendly last weekend.

"It's annoying but not the end of the world. There's always someone who can jump in," Klinsmann added.

The Germany stressed on the importance of Ballack to the Mannschaft but noted that he would be more useful when he is entirely fit, especially that the team has afformidable back-ups.

"We want him to get back to full fitness so that he can be fit for the other games in the competition.

"The important thing now is to look ahead. We want a fully fit Michael Ballack, not a 50 percent player. Fingers crossed he'll be back training soon," he added.

"We have different options with (Tim) Borowski and (Sebastian) Kehl. It is not a problem," Klinsmann added.

The 29-year-old former Bayern Munich midfielder missed the final match of the 2002 World Cup because of suspension.

Germany play in Group A alongside Costa Rica, Poland and Ecuador.