Manor Fields Park was cordoned off by officers after they were called out at around 5am today, when the body was discovered.
Scenes of crime officers have been among those on the site today.
Today, one resident told The Star they had been told by officers that the incident was believed to be a stabbing.
Police have yet to confirm details of how they believe the person died.
Members of the public were today being urged to avoid the area.
Anyone with information is asked to call South Yorkshire Police on 101, quoting incident number 122 of May 12.