Borussia Dortmund sporting director Sebastian Kehl has confirmed new striker Sebastien Haller has been ruled out of action for 'a few months' after he began treatment for a testicular tumour.
The former West Ham forward, 28, complained about feeling unwell following training last Monday and immediate medical examinations detected the tumour.
The Ivory Coast international joined Dortmund from Ajax earlier this month for a reported £27million, making him the most expensive striker in the German club's history.
Haller's Dortmund debut has been delayed as a result of the treatment following the shock diagnosis.