Borussia Dortmund signed Sebastien Haller this summer to bolster their attack after losing Erling Haaland. But, in an unfortunate turn of events, he will be out until the end of the year at the very least. The Frenchman has been diagnosed with a malignant tumor on his testicles and is set to undergo chemotherapy to treat it.

Via Fabrizio Romano:

Awful news for Haller, who was hoping to play a key part for Dortmund this term. On a more positive note, it's not seen as life-threatening. The former Ajax man was clinical last term in the Netherlands, scoring 21 goals and contributing seven assists in 31 league appearances. In the Champions League, Sebastien Haller absolutely flourished, netting a mind-boggling 11 times in eight matches.

The only focus right now is for Haller to get healthy. Chemo takes quite the toll on your body therefore it's safe to say we won't see him on the pitch for Dortmund until 2023. He did have surgery on the tumor recently but the chemo is also required to make sure it's gone completely.

Dortmund begins their 2022-23 campaign next weekend against Bayer Leverkusen. Once Haller does return, he should have no problem fitting in. After all, he did play for Eintracht Frankfurt for several years therefore he's familiar with the Bundesliga.