Officers were called to The Pocket sports bar in Mexborough at 12.30am on Sunday following reports that a man had been assaulted.
A 42-year-old man suffered serious injuries and was rushed to hospital where he remains at this time.
Two men, aged 26 and 22, have been arrested on suspicion of GBH without intent.
The 26 year old has been bailed and the 22 year old has been released under investigation, a police statement said.
It added: “Following a number of concerns being raised, a closure notice was issued to The Pocket on Monday."
There will be a licensing hearing at Doncaster Magistrates Court later this week on the pub’s future.
The bar, also known as The Corner Pocket, is situated in Bank Street in Mexborough and is also a sports and snooker hall.