Sonny Bill Williams says his former rugby league coach Steve Folkes was at the centre of his decision to abandon the Bulldogs and take up a rugby contract with Toulon.
In an interview to be shown on Channel Nine's Footy Show Williams says he was angered when Folkes questioned his friendship with the boxer Anthony Mundine earlier in the year.
He says after showing no interest in his personal life Folkes said "you're not turning Muslim are you?" and then criticised Mundine.
Williams says he hasn't been happy at the Bulldogs for a while.
But Folkes says Williams will do anything to try to justify his behaviour, which has been indefensible.