GENEVA, May 28 (Reuters) - Michael Ballack and Robert Huth are doubts for Germany's next World Cup warm-up against fellow finalists Japan in Leverkusen on Tuesday.
Ballack, the Germany captain, suffered a minor ankle strain in a practice game last Thursday and was forced to miss Saturday's 7-0 win over Luxembourg in Freiburg.
He had been expected back within a couple of days but he missed training again on Sunday.
'It's too early to tell whether he will be able to play against Japan,' assistant coach Joachim Loew told reporters at the team's training camp in Switzerland on Sunday. 'We'll decide on Monday at the earliest.
'He came through some intensive individual sessions while we were in Germany and it's a bit better but he is still feeling some pain.'
Centre back Huth also came out of the Luxembourg game with an ankle problem, while striker Oliver Neuville has a less serious thigh strain.
Philipp Lahm, first choice left back for the World Cup hosts, has yet to recover fully from the elbow injury he suffered on May 16.
'The scan on Huth's ankle revealed nothing dramatic,' Loew said. 'Thankfully there's no tear but again, it's too early to tell whether he can play.'
Neuville's thigh injury was 'no real problem', according to Loew.
Ballack will join Chelsea after the World Cup, following his move on a free transfer from Bayern Munich.
The injury news dampened the mood at the German camp following their enjoyable victory over Luxembourg.
Miroslav Klose and Lukas Podolski led the attack with two goals apiece and Neuville came off the bench to score two in less than a minute of injury time. Torsten Frings got the other goal on his 50th international appearance.
'Japan and Colombia are of a completely different calibre to Luxembourg,' Loew said.
'But of course we can be positive about the performance. It was nice to see that the players have learned a lot from the things we've been working on here in Geneva.'
Germany leave Switzerland on Tuesday and head straight to Leverkusen for the game against Japan. They then set up camp in Duesseldorf for a couple of days before playing Colombia in Moenchengladbach on June 2.
They play the opening match of the World Cup against Costa Rica in Munich on June 9, with further Group A games to come against Poland and Ecuador. The final is on July 9 in Berlin.