The attack, which took place outside a bar in Christchurch, left Ryder, who came out of a coma on Saturday, with injuries including a punctured lung and a fractured skull, the Age reports.
According to Ryder's manager Aaron Klee, Ryder has left the hospital and is back at his home in Wellington, New Zealand.
Meanwhile, Ryder has told the police that he has no recollection of the assault that left him fighting for his life.
The attack happened around midnight last Thursday outside the bar, where Ryder had been out for a drink with his Wellington teammates.
A second attack took place across the road at the entrance to a McDonald's car park.
In March 2012, Ryder took a break from international cricket, after admitting he had a drinking problem, the report added.