Borussia Dortmund attacker Mario Gotze has been ruled out for the foreseeable future as medical tests revealed the muscular problems he has been suffering in the last few months have caused "metabolic disturbances."
Gotze, 24, returned to Dortmund in the summer after a disappointing three-year spell with Bayern Munich, but he has not yet been able to match the performances he produced during his initial stint at the Westfalenstadion.
The problems have so far limited Gotze's time on the pitch to only 24 minutes in 2017 and a medical investigation has now shown the cause.
"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.
"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," Gotze said.
Borussia Dortmund's sporting director Michael Zorc added: "We're happy to have now uncovered the reasons for Mario's difficulties and are convinced that his extraordinary abilities will give us additional quality once he has completely recovered from this. Mario has the full backing and maximum support of everyone at BVB during his recovery!"
Gotze has again been linked with a reunion with former Dortmund boss Jurgen Klopp at Liverpool, while the Germany international is also reportedly a target for the Chinese Super League.