Theo Zwanziger admits that he had serious doubts about the former Tottenham striker's ability as a coach during World Cup 2006 and had been planning to replace him
The 67-year-old has written a book about his time in charge of the organisation and claims that a contingency plan to install Matthias Sammer as boss was drawn up.
"I have to admit that I was beginning to have doubts about our team coach. Publicly, I expressed loyalty to Klinsmann, but internally, we set up a plan B," an excerpt from the book, published in Bild, read.
"If there would have been looming a disaster in 2006 and we couldn't have hold on Klinsmann, we decided that Sammer should replace him on short notice.
"If it would have come that far, we would have told him early enough. Fortunately, we were not forced to do this."
Germany reached the semi-finals in 2006, with current boss Joachim Low replacing Klinsmann shortly after the tournament.