Borussia Dortmund midfielder Mario Gotze has been ruled out of action "for the time being" because of "metabolic disturbances".
The 24-year-old has been limited to nine Bundesliga starts because of muscular problems since re-signing from Bayern Munich last summer.
Dortmund confirmed that they had carried out a series of internal investigations into the cause of Gotze's issues.
"Those investigations revealed the player has metabolic disturbances, rendering it absolutely necessary to withdraw him from team training for the time being," a statement read.
"We are glad to know the reasons for Mario's complaints and we are convinced that after recovering he will give us extra quality with his exceptional abilities," said Dortmund director of sport Michael Zorc.
"Mario gets the full backing and maximum support from all of us at Borussia Dortmund on his way back."
Gotze, who scored Germany's extra-time winning goal against Argentina in the 2014 World Cup final, has played just 24 minutes of Bundesliga action in 2017.
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