Blues rookie Rene Ranger has been stood down for this weekend's Super 14 match against the Reds as part of a misconduct investigation into a late-night incident.
The 22-year-old was allegedly involved in a street fight in Matakana, north of Auckland, on Saturday.
Police are also investigating, but saythere will be no charges until witnesses are spoken to.
Warkworth Police Sergeant Bede Haughey said police had spoken to a 22-year-old Northland man, who was "assisting with inquiries" into an alleged assault on Matakana Rd about 2am last Sunday.
It is understood a 26-year-old local man was knocked out.
A St John spokesman confirmed paramedics attended the scene and transported a man to North Shore Hospital for observation. Police said the man discharged himself later that day.
NZRU general manager professional rugby Neil Sorensen said yesterday the union and the Blues had started a misconduct investigation into the incident, and Ranger had accepted that it would not be appropriate for him to be playing this weekend.
"Together with the Blues team management we will also hold a misconduct hearing with Rene to determine exactly what happened.
"Once we have ascertained the facts we will then determine any penalty deemed appropriate."
Mr Sorensen said the NZRU was "incredibly frustrated and extremely disappointed" at ongoing incidents of misconduct involving its professional players.
"We have had far too many incidents recently and, frankly, enough is enough."
