Officers were called by paramedics after a seriously injured man in his 20s, was found on Darkhouse Lane, Coseley, at around 11.30pm on Wednesday.
The road was closed off throughout Thursday, while nearby Rosewood School was also shut.
A West Midlands Police spokeswoman said: "A scene was held while we conducted forensic examination and we are reviewing CCTV to determine exactly what happened."
A spokeswoman for West Midlands Ambulance Service, said: "We were called at 11.17pm to the junction of Webb Street and Darkhouse Lane, Coseley. An ambulance, two paramedic officers and a MERIT trauma doctor attended.
"A man, who had sustained a serious injury, was given trauma care by the team of ambulance staff on scene before being conveyed on blue lights to hospital for further care."
Rosewood School headteacher, David Kirk, said the incident prevented access on Thursday, leading to the decision to close the school.
However he said they would be reopening as usual on Friday.
Anybody with information is urged to contact the force on its website or by calling 101 and quoting reference number 4374 of May 25.