Police officers discovered the man at Kviberg cemetery at 8pm.
“It was just by chance that the unit went by there. We don’t think it’s the crime scene; the man was probably dumped there. It’s a very concealed place,” inspector Mats Jarlhede told news agency TT.
The man was taken by ambulance to Sahlgrenska Hospital before being questioned by police.
The 22-year-old later told police he had been attacked from behind and did not remember anything. None of his personal belongings were stolen.
“It’s always difficult in cases like this where information is so thin of the ground. But we have secured some leads, so we’ll see where those take us,” inspector Ulf Strahl told local newspaper Göteborgs-Posten.