Germany coach Joachim Low has voiced his concerns that Bayern Munich's appearance in this season's Champions League final could harm his side's preparations for the European Championships.
The Germany squad is due to be announced on May 7 and will meet up three days later to begin their training for the tournament.
However, with the Champions League final taking place on May 19, the Bayern contingent will be forced to join the squad late and are unlikely to be available for the friendly against Switzerland on May 26.
"If they do come, then they are not going to be ready to play immediately," Low told newspaper Suddeutsche Zeitung.
"They will first need to catch their breath and we will have to decide when they start training with us.
"It would have been ideal to have three and a half weeks together with the full squad, but I just have to deal with the situation."
Bayern are expected to make up a substantial part of Germany's 23-man squad, with Philipp Lahm, Bastian Schweinsteiger, Jerome Boateng, Manuel Neuer, Holger Badstuber, Thomas Muller and Toni Kroos all likely to be on the plane to Poland and Ukraine.