A 39-year-old man was shot in his leg as he walked across the forecourt of Jet petrol station in Woodhouse Mill on Tuesday morning.
Detectives are treating the shooting as a targeted attack.
The victim was blasted in his leg by the passenger of a black Seat Leon, which pulled up alongside him.
The gunman and his driver have not yet been caught.
A South Yorkshire Police spokeswoman said: "Detectives are continuing to carry out forensic work and enquiries in the area, including speaking to witnesses and analysing CCTV footage of the surrounding area.
"The offender is still outstanding."
Anyone with information about the incident at 9.10am on Tuesday should call South Yorkshire Police on 101 or Crimestoppers on 0800 555111.