Emergency services were called to Cope Street, Barnsley, at about 7am on Sunday morning, police confirmed.
The 69-year-old man was taken to hospital where he remains in a critical condition.
A police spokesman said: “Detectives are appealing for witnesses after a man was seriously injured in Barnsley over the weekend.
“Two men, aged 26 and 30, both from Barnsley, have been arrested on suspicion of assault and remain in custody.
“Enquiries are ongoing to establish exactly how the man suffered his injuries and officers would like to speak to anyone with information.
“We are particularly keen to speak to anyone who may have seen something suspicious in the early hours of Sunday morning in the Cope Street area.
“If you were in the area at the time and saw what happened, call 101 or Crimestoppers anonymously on 0800 555111 quoting incident number 337 of October 27.”