After four years at Mainz, Jean-Paul Boetius went to Hertha in August, and his new club promised "full support" for his recuperation.
After testing confirmed that Dutch winger Jean-Paul Boetius has a testicular tumour, the Hertha Berlin player will have surgery on Friday.
The 28-year-old former Feyenoord and Basel player, who has received one Netherlands national team cap, joined Hertha in August following a four-year stint with Mainz.
In a statement, his team stated: "According to the findings of a urological examination on Wednesday, Jean-Paul Boetius has a testicular tumour and will be sidelined for some time. On Friday, the 28-year-old will have surgery."
Boetius has the support of Hertha's managing director of sport, Fredi Bobic, to fully recuperate.
Bobic said: "As tough as it is to hear at first, we are full of hope that Jean-Paul will be able to recover and return to us as soon as possible.
"He will receive our full support, until he returns. The Hertha family are by his side and wish him all the best."
The news for Boetius follows Borussia Dortmund striker Sebastien Haller being found to have a testicular tumour in July, just weeks after joining from Ajax. Haller had surgery and has since undergone chemotherapy.