Schalke 04 midfielder Leon Goretzka has suffered a recurrence of a leg injury, putting a January transfer in doubt.
The 22-year-old has drawn interest from across Europe ahead of the winter window, with Manchester United, Liverpool and Arsenal all said to be keen to bring him to England, while Barcelona and Juventus are also reportedly poised.
However, there is now doubt that Goretzka will be able to pass a medical in the near future as the German club have revealed that he faces a spell on the sidelines.
"Leon Goretzka has suffered a recurrence of the injury in his lower leg," the club tweeted.
"In order to put these continuous and worsening pains to bed, Leon will undergo examinations over the coming days.
"Until then, it is unclear as to when Leon will be fit to train and play once again. Get well soon, Leon."
Goretzka, whose current contract expires in the summer, has made 12 appearances in the Bundesliga so far this season, scoring six goals.