Borussia Dortmund have confirmed striker Sebastien Haller is to undergo chemotherapy after examinations revealed a testicular tumour to be malignant.
The former West Ham forward is now expected to be out of action for several months. The tumour was diagnosed earlier this month after Haller complained of feeling unwell after training.
Dortmund sporting director Sebastian Kehl told the club’s website: "Sebastien will now receive the best possible treatment. The chances of recovery are very good.
"We wish him and his family a lot of strength and optimism and our thoughts are with him during this difficult time.”
A statement from the club read: "Sebastien Haller (28) will be absent from Borussia Dortmund for several months. The histological findings revealed a malignant testicular tumor. Haller therefore has to undergo chemotherapy treatment."
Haller had only moved from Ajax to Dortmund in a reported £27million deal this month. He scored 32 goals in 36 appearances in all competitions last season. He spent one-and-a-half seasons at West Ham, making over 50 appearances, before the Hammers sold him to Ajax for £20.25m in January 2021.
"We're very pleased that in Sebastien Haller we've been able to sign a proven centre forward who recently made waves in the Champions League, but who also knows the Bundesliga and has already demonstrated his class and top-quality finishing ability in the league," Kehl had said when the move was confirmed.
However, the forward has now been ruled out for several months. Dortmund midfielder Jude Bellingham and Haller's former West Ham team-mate Declan Rice were among those who tweeted their support.
Bellingham said: "Stay strong and get better soon brother, we're all with you!" Rice said: "Thoughts are with you my brother! Praying you have a speedy recovery."
"Thank you all for your many messages of support and affection since yesterday's announcement," Haller said on July 19. "My family and I thank you. I will now focus on my recovery to come back stronger."
"I want to thank you again from the bottom of my heart for all these many warm messages received. I was very moved to see these beautiful reactions and I even feel like I don't deserve so much.
“But I know that thanks to you it will only be one more test on our way. See you very soon in the ground to celebrate our next victories."
