WESTS Tigers forward Simon Dwyer, one of the NRL's brightest prospects, faces a significant battle to play again after test results indicated he required major surgery to repair nerve damage.

The Sun-Herald understands specialists have told the 22-year-old that he is unlikely to play again, following the results of a ''nerve conduction'' test to assess the damage to nerves in his right shoulder and arm.

Dwyer, who shot to prominence after a tackle on Roosters forward Jared Waerea-Hargreaves in a qualifying final last year, suffered the damage against the Bulldogs in round 16.

But it was Dwyer's very ability to hit hard that contributed to his condition - the sort of brachial plexus damage he suffered in the tackle on Bulldogs forward Michael Hodgson on June 24 is usually seen in high-impact motorbike or skiing collisions. Balancing safety and aggression has been one of the challenges for the Tigers and Dwyer.

Medically, there are few sporting precedents for the club to go by, although the Tigers' medical staff have been researching Dwyer's type of injury since that match against the Bulldogs.

Dwyer, earmarked by Blues coach Ricky Stuart as a future State of Origin player, still does not have full movement in his right hand and arm, and is focused for now on regaining that movement. Only then would he realistically be able to consider playing again. If he has surgery - which involves grafting nerve tissue from another part of his body to the damaged nerve - it is believed Dwyer would not be able to play for several years, if at all.

The results of the conduction tests, carried out on the advice of neurosurgeon Dr Michael Biggs at Royal North Shore Private Hospital just over a week ago, have thrown more scientific doubt on one of the most promising careers in the code.