ON THE eve of his New Zealand heavyweight title fight tomorrow night, Sonny Bill Williams, pictured, has revealed he suffered a hamstring tear training under the former Sydney Roosters sprint coach Roger Fabri.

While Williams insists the injury has not hampered his preparations for the bout against the former NFL hopeful Clarence Tillman, news that he had been training under Fabri will only heighten speculation he is set to join the Roosters next season. Fabri has teamed up with the Roosters' captain, Braith Anasta, to establish the Speed Agility Academy and he trains a number of players from the Bondi club.

Parramatta duo Reni Maitua and Willie Tonga, who played alongside Williams at the Bulldogs and remain close friends of the World Cup winning All Black, also do sprint training under Fabri.

''I always wanted to do a bit of pure speed training and Reni and Willie said he was all right so I did some work with him,'' Williams said.

''I hadn't done speed work since I was 18 so it was good but I went a bit too hard one day after 10 rounds of sparring the night before and pulled my hammy.

''When I was in Sydney I was doing a bit of speed during the day because it was relevant to my rugby and at night I would do boxing.''

Williams, who quit the Bulldogs to play rugby four years ago, is contracted to the NZRU until the end of the season and will play super rugby for the Chiefs.

''The coaching staff and everyone at the Chiefs have been really understanding and great as to what I need to do for training and things like that,'' Williams said.