Jamie Adam Kelly, aged 30, from Leeds, died in hospital on Monday.
South Yorkshire Police said that it had been reported at 9.40pm on Sunday that a man was ejected from the Vintage Rock Bar on Silver Street, in Doncaster town centre.
Police said a physical altercation then took place with three other men outside.
Mr Kelly sustained serious injuries and police officers provided CPR at the scene until paramedics took him to hospital where he later died.
A post-mortem examination is due to take place on Tuesday.
A 40-year-old man from Worksop, a 26-year-old man from Nottingham and a 33-year-old man from Doncaster were initially arrested at the scene on suspicion of Section 18 assault.
On Monday they were all further arrested on suspicion of murder.
Police said the three have now been released on bail.
Last night a fourth man, a 20-year-old from Doncaster, was arrested in connection with the incident. He has also been bailed.
Anyone with information is asked to call South Yorkshire Police on 101 quoting incident number 875 of May 1.
CCTV or mobile phone footage can be emailed into [email protected], quoting the incident number in the subject line. People can also pass information directly to the incident room via https://mipp.police.uk/operation/14SY22A02-PO1
Alternatively, contact Crimestoppers anonymously via its website Crimestoppers-uk.org or by calling 0800 555 111.