Schalke midfielder Leon Goretzka has once again gone down with an injury.
But the club have confirmed that the Germany international has aggravated the injury and will be out for the foreseeable future.
"Leon Goretzka has suffered a recurrence of the injury in his lower leg," Schalke said on Wednesday.
"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!"