Borussia Dortmund coach Jurgen Klopp has admitted he is disappointed Japan midfielder Shinji Kagawa has been called up for his country's friendly against South Korea next Wednesday.
Kagawa missed the first half of the year after breaking a bone in his foot during January's Asian Cup and has worked his way back to full fitness for the German champions ahead of the new season.
Dortmund begin their defence of their Bundesliga crown against Hamburg on Friday.
Kagawa impressed during Dortmund's 3-0 German Cup win over minnows Sandhausen last Saturday, but the 21-year-old now faces return flights to Japan for the friendly against South Korea, something Klopp would have preferred him to avoid doing.
"It's not a good thing when he faces a long journey after our first league game and then returns to play week next Saturday," said Klopp.
After the game against Hamburg, Kagawa will jet off to Japan before returning to face Hoffenheim on Saturday August 13.
"We had feared this would happen," said Dortmund spokesman Josef Schneck.
"But he wants to go and we can't stop him. I hope he comes back healthy."
Dortmund were already dealt a blow at the start of the week when they discovered Paraguay striker Lucas Barrios is more seriously injured than first thought and will be out for up to six weeks.
The 26-year-old suffered a thigh-muscle tear during Paraguay's Copa America final defeat to Uruguay on July 24.