Officers were called to Silver Street on Sunday at about 9.40pm ‘in response to an incident which took place following the ejection of a man from Vintage Rock Bar by members of the door staff.’
Police said the man was found to have sustained significant injuries in an incident which is believed to have taken place outside the premises.
In a statement, South Yorkshire Police said: “Officers administered initial first aid at the scene and the victim was subsequently transported to hospital by Yorkshire Ambulance Service where he remains in a critical condition.
"A 40-year-old man from Worksop, a 26-year-old man from Nottingham and a 33-year-old man from Doncaster have been arrested on suspicion of Section 18 assault and remain in police custody at this time.
“Enquiries are ongoing. Officers would like to speak to anybody who may have been either inside or outside Vintage Rock Bar at the time who may be able to assist the investigation.
"Anyone with information is asked to call 101 quoting incident number 875 of 1 May. CCTV or mobile phone footage can be emailed into [email protected], quoting the incident number in the subject line.
"You can also pass information directly to the incident room using the public portal here: https://mipp.police.uk/operation/14SY22A02-PO1”
Pictures and video footage has since emerged from the scene which appears to show police officers tending to a man on the ground.