There is his height; rugby league does not lend itself to many 6ft 5in giants. There is the name - a gift from a father with a penchant for eccentric spelling as well as for Welsh stand-offs. And there is the background - a fee-paying school on the Fylde Coast rather than the local comprehensive.
Mather's displays this season in two contrasting roles for Wigan have confirmed him as a young man whose talent is exceptional as well.
He began the season in the second row, scoring six tries in the first five matches as he seemed finally to have beaten off the ferocious competition for a place in Wigan's pack. But the new Wigan coach, John Dorahy, had other ideas and decided after Dean Bell's groin injury, that Mather could be equally effective in the centre.
'My feeling at the time was that I could hold down a place in the second row, but I wasn't too worried about making the switch,' Mather said. 'It's not as big a difference as you might think.'
As a threequarter, Mather again faces a battle for his place. Va'aiga Tuigamala is being widely tipped to make his debut for Wigan in the Silk Cut Challenge Cup tie against Wakefield Trinity next Sunday.
On the face of it, Mather must start as strong favourite to make way for the former All Black. After all, the other Wigan threequarters - Jason Robinson, Gary Connolly and Martin Offiah - are all current Great Britain internationals.
But Mather has seemed astonishingly comfortable in his new role. At Headingley last Friday, on the eve of his 21st birthday, he was Wigan's most damaging player, running Leeds ragged down the right with his long-striding gallops.
'I dislocated my finger and I was a bit disappointed with my second half,' said a player who has learned there is no room for excessive self- satisfaction at Wigan. 'But I'm pleased with the way it's going.'
He has grown up amid the culture of competition, so the prospect of Tuigamala breathing down his neck does not discourage him any more than it did to dispute a second-row place with, at the last count, four internationals.
If anything, he errs on the side of impatience. When it looked, briefly, as though he might fall between the two stools of the pack and the back- line, he talked at length to the Auckland Warriors. Wigan responded with amuch-improved contract.
With five A-levels from his time at Arnold School - where he also played rugby union for England Schools at under-18 level - Mather is now in the middle of his degree course at Liverpool University.
As his team-mate, Phil Clarke, another example of the educated face of rugby league, found out, it is a strange lifestyle; poring over your notes in a corner of a student house one minute, fielding questions about a cup final the next.
But BJ - as he is known - shows every sign of being able to handle it all, be it his second-year exams next week or the test he faces this afternoon.