A homeless man arrested for slugging another vagrant could now face murder charges — because an autopsy shows his victim died of injuries from their fight, the NYPD said Monday.

Jeremiah McCarthy and Constanin Palaghia, both 54, got into a dispute Oct. 6 around 8 p.m. on the corner of Seneca and Myrtle avenues in Ridgewood, Queens, cops said.

The fight ended when McCarthy punched Palaghia and the man fell over and slammed his head on the concrete, police said.

Palaghia was transported to an area hospital, where he succumbed to his injuries Thursday, cops said.

McCarthy was initially arrested Friday on assault charges pending an autopsy on Palaghia.

The autopsy results came back Monday showing Palaghia died of injuries from his fall during the fight, and police said they now expect to upgrade the assault rap against McCarthy to murder.

The attack on Palaghia happened the same week that a homeless man murdered four vagrants with a pipe in Chinatown, and another drifter with a history of mental illness body-slammed a 6-year-old boy in Queens, critically injuring him, authorities have said.