Sebastien Haller has left Borussia Dortmund’s pre-season training camp in Switzerland after a tumour was found in his testicle, says the German club.
The 28-year-old Ivory Coast international recently joined the Bundesliga side from Dutch club Ajax.
Dortmund said Haller “complained that he felt unwell after training on Monday” and, following medical tests, “a testicular tumour” was discovered.
Further examinations will now take place “over the coming days”.
“This news today came as a shock to Sebastien Haller and everyone else,” said Dortmund sporting director Sebastian Kehl.
“The entire BVB family hopes that Sebastien makes a full recovery as soon as possible and that we can give him a hug again soon.
“We’ll do everything in our power to ensure that he receives the best possible treatment.”
Haller joined Dortmund earlier this month from Ajax, with Dortmund paying an initial €31m for a player they targeted to replace Erling Haaland. The France-born Ivory Coast international scored 34 goals for the Dutch side last season, including 11 in eight Champions League games.
Following Dortmund’s announcement, Ajax simply tweeted “Seb” with heart and prayer emojis. West Ham, where Haller played from 2019 to 2021, tweeted: “We’re with you, @HallerSeb. Wishing you the best with your recovery.”