A 22-year-old man has been arrested on suspicion of assault after the office was reportedly assaulted in Farquhar Road, Maltby, on Tuesday night.
He was also arrested on suspicion of making threats to kill and remains in custody today (Wednesday).
South Yorkshire Police said the officer regained consciousness and was taken to hospital.
He is not believed to have suffered any serious injuries.
A second man, aged 24, was arrested on suspicion of assisting an offender in connection with the incident and also remains in police custody.
A spokesperson for South Yorkshire Police said: “We would like to thank local residents for their help last night and for their continued support.”