Ghana midfielder Kevin-Prince Boateng is racing to be fully fit for the start of the Bundesliga.
Boateng, 27, has not trained with his Schalke side after gastrointestinal problems hit him following their German Cup game on Monday.
Team boss Jens Keller had said he will wait out Boateng’s illness before making a call as late as possible.
Boateng, who has been declared persona non grata by Ghana’s FA following disagreements at the last World Cup, is expected to be a talisman for the German side.