Hoffenheim coach Markus Babbel believes Germany coach Joachim Low has been "betrayed" by a mole in the Germany camp who keeps revealing the team selection hours before the games are due to take place.
Low's starting XI became public knowledge over six hours before their Euro 2012 quarter-final clash with Greece on Friday, infuriating the coach and members of the team.
Babbel told Sport1 that the leaks are "frustrating, unnecessary and stupid".
Low believes that one of the players' friends or agents is passing on the confidential information and he has already told them to be more careful with who they talk to ahead of Thursday's semi-final clash with Italy.
Babbel hopes that the mole will also have a conscience and realise that what they are doing is jeopardising Germany's chances of glory in Poland and Ukraine.
"We all have the goal of becoming European champions," he said. "If there is somebody there spreading things like this, then he is not doing German football any favours.
"At the end of the day, we all suffer because of it."
Germany captain Philipp Lahm said what is discussed in the team meeting at lunchtime before the game "should remain within the four walls".
At a press conference in Gdansk, he added: "It is a shame when things leak out.
"The whole nation wants us to go far and it is not an advantage when the team is revealed hours before the game.
"Whoever is revealing this has not understood what sport is. It's definitely a shame."
Low made four changes to his side for the quarter-final clash, saying he wanted his side to be more "unpredictable".
Further alterations can be expected against Italy in Warsaw on Thursday.