The 26-year-old was critically injured after he was shot in his upper body in an altercation outside the Wenue6, formerly the Forum, on Sandstone Road, Wincobank.
He was shot at around 1am yesterday.
Last night he remained in a critical condition in hospital and the gunman who opened fire remained at large.
Police officers cordoned off the crime scene yesterday as detectives attempted to piece together the exact circumstances surrounding the attack.
Anyone with information should call South Yorkshire Police on 101 or Crimestoppers, anonymously, on 0800 555111 quoting incident number 46 of April 28.