Hayman was arguably the world's best tighthead prop from 2004-07, but then walked away from New Zealand rugby before he turned 28 to play for Newcastle in the English Premiership and then ultimately Toulon.
Immortalised as the 1000th All Black on his 2001 debut, Hayman perplexingly lost favour with coach John Mitchell for much of 2002-03, before Graham Henry reignited his international career.
There was widespread disappointment, though, when Hayman walked away from it all after the 2007 Rugby World Cup failure. Henry later commented that a player could not be the best in the world if he was plying his trade for Toulon, although that jibe was not necessarily directed at Hayman.
Somerville was a fellow tighthead and ironically benefited with more starts in 2002-03 and in 2008 when Hayman was out of the All Blacks picture. Somerville could play both sides of the scrum and the pair would often be subbed for the other.
"We were vying for the same position most of the time, so it would have just been the odd grunt to each other as we left or ran onto the field," said Somerville, who himself racked up 66 tests in an under-rated career.
He feels Hayman's early departure from New Zealand rugby did not hinder his rating or legacy.
"He would have to be one of the top tightheads we've produced. If he'd hung around he would have played a helluva lot more test matches. We didn't want him to go, because he left in the prime of his career. He then went and scrummed well in the Premiership and in the Top 14 for several years," said Somerville, declaring that Hayman would rate in the top five.
Naming that top five is difficult to gauge, given, for example, that the late John Drake, a master scrum technician, played just eight tests. But Hayman is fit to be mentioned alongside the Ken Grays and Olo Browns of the rugby world.
"I don't think he was under-appreciated. Some guys back in the day might have played less tests but still made a great impact. It's what you do in those tests that counts, not the number you have. He didn't have too many dud games. All the guys who played with him fully appreciated him for what he could bring,' said Somerville.
"Carl's scrummaging was top-notch, especially later in his career when his technique was sounder - because he was tall for a tighthead - and not many could shift him. He was also a great lifter with that extra extension. He could do his core roles really well. Off the field he was a quiet guy, but on the field he was showing up with carries and his allround game came to the fore around 2006-07."
There had been some talk of Hayman returning to play in New Zealand, perhaps for his native Taranaki province, but that appears to be off the agenda.
"I suppose he wants to be able to climb on a quad bike on his dairy farm when he gets back," quipped Somerville.
Hayman was never a slick ball player, in the mould of the mobile John Afoa, now one of the world's highest paid players with Gloucester, but his value at the set-piece and in the collision was highly valued, more so later in his career and in the dark places of French club rugby, where he plies his trade with fellow 2007 World Cuppers Ali Williams and Chris Masoe.
His stonking 2004 All Blacks trial propelled him back into the black jersey, and few can forget the demolition job, anchored by Hayman, on the French front-row in Paris later that year.
Carl Hayman
45 tests, All Blacks (2001-2007).
68 caps, Otago (1998-2007).
81 caps, Highlanders (1999-2007).
2 caps, NZ Maori.
64 caps, Newcastle (2007-2010).
127 caps, Toulon (2010-2015).
