The Borussia Dortmund forward Sébastien Haller has a testicular tumour and has left his new club’s preseason training camp in Switzerland. In an official statement, Dortmund said that the 28-year-old first complained of feeling unwell at training on Monday. The tumour was found during a medical examination, with Haller returning to Germany to undergo further tests. Tumours can be benign and do not always lead to a diagnosis of cancer. “This news today came as a shock to Sebastien Haller and everyone else,” the club’s sporting director, Sebastian Kehl, said. “The entire BVB family hopes that Sébastien 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.”