Manuel Neuer is a "gigantic risk" for Germany at the World Cup, according to Oliver Kahn.
Germany coach Joachim Low named Neuer among four goalkeepers in his initial squad for the World Cup, giving the Bayern Munich player a chance to prove his fitness.
Neuer has not played since September due to a foot injury but could be named in Bayern's squad for Saturday's DFB-Pokal final against Eintracht Frankfurt.
But Kahn, who won Euro 1996 with Germany, says Neuer should not start at the World Cup due to the lack of games he has played this season.
"To judge it finally, I should have to see him in the daily training work," Kahn said to Spox and DAZN.
"But it is actually impossible and unthinkable, that he can make a good performance.
"But because of his achievements in the past, he is trusted to do so, it was right for Low to take him with him and see him.
"Even if he plays two international matches, it is still a gigantic risk that everyone has to be aware of and he has to ask himself: is it really worthwhile to play a World Cup after a break of eight months? A blatant decision he has to make."
The main rival for Germany's gloves is Marc-Andre ter Stegen, who has developed into a high-class goalkeeper at Barcelona.
"He has managed to prevail at Barcelona, that alone is a great achievement," Kahn said.
"In the national team it was a hard journey for him, he started with many mistakes. That means he did not have the self-confidence at the time.
"The Confederations Cup, which he has played with stability, and the experience of Barcelona, means he is fully arrived and fully accepted.
"This is another stage than at the beginning of his national team career. I'm not worried if he has to play the World Cup."