Melbourne - Wallabies hooker Tatafu Polota-Nau could take a long leave of absence from rugby or even the quit the game entirely if he suffers another heavy head knock.
Polota-Nau, who has been working with Australian neurologists on the effects of concussion, was forced from the ground with a head injury early in the Waratahs' Super Rugby win over the Brumbies in Canberra on Friday.
The 29-year-old was also forced to miss a couple of games in the southern hemisphere's provincial championship earlier in the season after suffering another blow to the head at training.