Officers believe the driver and occupants of the vehicle could hold vital information about an incident in which a cyclist sustained serious injuries.
The 55-year-old cyclist was found slumped on a path under a railway bridge on Prince of Wales Road on at 8.38pm on Saturday, September 26.
It is understood that the cyclist was travelling towards Darnall from the general direction of the A57 Parkway when he sustained his injuries.
Officers now wish to trace the occupants of a black people-carrier type vehicle, which was seen on CCTV travelling along Prince of Wales Road towards Darnall shortly before the incident.
The cyclist was taken to hospital, where he remains remains in hospital in a serious but stable condition over two weeks later.
Lead Investigating Officer, Acting Police Sergeant PC Martyn Mickelthwaite, of South Yorkshire Police, said: “We know that the vehicle in the CCTV released was driving behind the cyclist as he headed down Prince of Wales Road.
“We believe the driver may have information that can help us with our enquiries and piece together into how the man became injured.”
Anyone with information about the incident or whereabouts of the black vehicle should call 101 and quote incident number 922 of September 26.
CCTV or dash cam footage of the cyclist, black vehicle or incident should email it to [email protected], quoting the same incident number.