Basel striker Ricky van Wolfswinkel is undergoing treatment for a brain aneurysm that was only discovered after he had scans following a concussion.
The Dutchman, 30, says he is facing “at least six months” out of the game.
The aneurysm is a pre-existing condition and not caused by the severe concussion he sustained near the end of Basel’s Champions League qualifying match against LASK on 7 August.
“I’m very grateful the brain aneurysm got discovered,” he said. “Normally a brain aneurysm is not discovered in time, only after it has ruptured and caused other damage.”