Rugby Australia said it was "aware of an incident which has resulted in the hospitalisation of Australian Men's Sevens player James Stannard in Sydney overnight".
Police say Stannard was standing outside the kebab shop when he was allegedly punched in an unprovoked assault, causing him to fall and strike his head on the pavement.
Australian rugby sevens captain James Stannard is in hospital after being the victim of an alleged coward punch attack at a late-night Sydney eatery.
Stannard was with a group of teammates, along with coach Andy Friend, at the time of the incident.
Stannard has suffered a fractured skull but is now in a stable condition at St Vincent's Hospital.
"When he (Stannard) fell to the ground he's done some damage to the side of his head, and the offender ran off", Insp Egbers said.
Following the incident, the 22-year-old perpetrator attempted to flee the scene, but was apprehended by witnesses until police arrived on the scene and placed him under arrest, according to a NSW Police spokesperson.
The blow brought back bad memories for Friend who was the Brumbies coach in 2009 when Shawn Mackay died from head injuries sustained in a road accident in South Africa.
CAMERON SPENCER GETTY IMAGES James Stannard won't be part of the Australian sevens' Gold Coast campaign when it begins on April 14
There are doubts whether James Stannard will play in the upcoming Commonwealth Games as he remains in hospital.
Friend was told earlier this month that his contract with the team would not be renewed in July, but RA said they hoped he would remain with the wider organisation.
"The team are obviously shocked", Rugby Australia high-performance general manager Ben Whitaker said.
"I've been a coach for 23 years I've been to a lot of those events where you smell something going wrong". Stannard was struck by a man in an unprovoked attack after reportedly having a conversation with him outside a fast food outlet, Rugby Australia said.
"I think at this point in time, personal choice of James and his family is that he'll look to stay another day, but all the indications are very, very positive for James, which is the most important".
Stannard had replaced the injured Holland as captain for the tournament.
Friend said Stannard would likely attend the Commonwealth Games in a support role for the team.