World Cup winner Mario Gotze has been ruled out "for the time being" because of "metabolic disturbances", his club Borussia Dortmund have said.
The Germany midfielder, 24, has been limited to nine Bundesliga starts because of muscular problems since re-signing from Bayern Munich last summer.
The club said that they had carried out a series of internal investigations into the cause of Gotze's problems.
Gotze said he would do "everything in his power to be back in training".
"He [Gotze] has continually suffered with muscular problems in the past few months, prompting a comprehensive internal investigation into the possible causes," said a club statement.
"Those investigations revealed the player has metabolic disturbances, rendering it absolutely necessary to withdraw him from team training for the time being."
Gotze, who scored Germany's extra-time winning goal against Argentina in the 2014 World Cup final, has played 24 minutes of Bundesliga action in 2017.
"I'm currently undergoing treatment and will do everything in my power to be back in training and helping my team to achieve our common goals as soon as possible," he said.
Dortmund are third in the Bundesliga table, 13 points behind leaders Bayern Munich with 12 matches remaining.