Police closed West Street at around 8.35pm after a man was attacked by a gang of men near to the Bar & Beyond.
The man was treated at the scene by paramedics, after hitting his head on the tram tacks, before being taken to hospital via an ambulance.
An onlooker said that the homeless man had asked the group of men for some money before they became aggresive and spat on him.
The onlooker said: "It was a beggar who asked these four men for some money, they said no and one of them spat on him. Then one of them punched him and the man fell back and hit his head on the tram tracks.
"Then the men ran away. The victim was being put on a stretcher into the back of an ambulance."
South Yorkshire Police said the man remains in hospital.
A police spokesperson said: "At this time, the extent of his injuries are not known however they are not thought to be life-threatening."