Oliver Kahn has raised doubts over Manuel Neuer's chances of playing for Germany at the World Cup.
Neuer is back in training but has not played for club or country since undergoing surgery on a broken foot last September, leaving national boss Joachim Low facing a tricky decision over whether to pick the experienced goalkeeper.
Outgoing Bayern Munich coach Jupp Heynckes said on Friday he was "very optimistic" over the 32-year-old's chances of participating in Germany's pre-tournament training camp.
Yet former international Kahn believes the player himself must consider carefully whether it is wise to be part of the squad after such a lengthy spell out of action.
"When he still does not play that's a clear sign he is not a 100 per cent fit yet," Kahn - who captained Germany in the 2002 World Cup final defeat to Brazil - said in an interview with Bild am Sonntag.
"Otherwise, he surely would have been given the chance to play from Jupp Heynckes.
"It's a hard decision for the responsible persons. And Manuel has to ask himself if he still does himself a favour with all this."
Marc-Andre ter Stegen has deputised in Neuer's absence for the national team, including their successful Confederations Cup campaign in Russia last year.
Kahn believes the Barcelona keeper is a reliable option for the World Cup too, if Neuer is not considered for selection.
"He is a very good keeper. You can trust him. We should not worry about him," he added.