A Cronulla Sharks player needed 20 stitches for a head wound sustained in a training altercation at the NRL club.
Jacob Selmes was taken to hospital with head injuries after an altercation with first-grade forward Hutch Maiava, according television news reports.
An inquiry is believed to be underway at the club.
Coach Stuart Raper confirmed the incident and the players involved.
He is expected to make a statement about the incident later this evening.
Sharks skipper Brett Kimmorley said he was unaware of the incident because the players had been training at different times in different skills groups.
"I suppose if it has happened then we'll have a meeting about it tomorrow to discuss what did occur," Kimmorley said.
An NRL spokesman said the game's governing body was also unaware of the incident but that it would remain a club matter if it had occurred at a private training session.
SMH