Bayern Munich boss Louis van Gaal has branded the decision to organise a four-day training get-together for the Germany squad next week as "madness".
National team coach Joachim Low named a 30-man squad on Thursday - to meet in Stuttgart on Sunday and return to their clubs next Thursday - as he looks to assess the condition of players he is considering taking to this summer's World Cup.
Five Bayern players - Philipp Lahm, Bastian Schweinsteiger, Thomas Muller, Mario Gomez and Miroslav Klose - are involved and, with a match against Mainz coming up next weekend, Van Gaal is unimpressed.
"I think this is madness," he said in Kicker. "We pay the players. Four days is not normal. I also have to prepare for a game. "I have never experienced anything like this before - and I have coached many top teams."