Musician Oscar Villagrana was visiting Australia to play a couple of jazz gigs, but ended up in a Melbourne hospital suffering massive head injuries after a violent assault.

The 32-year-old Californian man was the victim of the random attack last week after getting off a night-time tram in Preston, in the city's north.

American musician Oscar Villagrana who was bashed after stepping off a Melbourne tram.

Surgeons have had to extract excess blood from his brain, seal his fractured skull with metal plates and he will be left with a scar covering half his head.