Borussia Dortmund became the latest European club to frown on Japan's trip to the Copa America on Sunday, saying its injured star midfielder Shinji Kagawa needs a proper training camp this summer ahead of what will be his second Bundesliga season.

"Shinji is coming off a serious injury, and it's necessary for him to prepare with the team before the new season," Dortmund's sports director Michael Zorc said. "That would be the best decision in his interests.

"We have a very good relationship with the Japan Football Association. We talked to them when they came over to Germany for January, and we will certainly speak with them again this time."

Kagawa has not played since breaking his right metatarsal at the Asian Cup in Qatar in January, and the odds of him returning for leader Dortmund before the season's end on May 14 remain slim.

Manager Jurgen Klopp said earlier this week that Kagawa still can't even shoot the ball, and is able to only run in a straight line. He laughed off a report in Germany that had Kagawa coming back for next weekend's tie with Monchengladbach.