"As this stage I can't put a dollar figure to it but, you talk about game-wide, it is millions and millions and millions of dollars," said Roosters commercial chief Ted Helliar when asked to assess the value of Williams' return to the sport where he made his name.
"We had a record round-one Sydney gate and record TV ratings - that is all off the back of the Sonny Bill factor. Our membership numbers are up 25 per cent and that has definitely been Sonny.
"We have budgeted vast increases right across the board. We are looking at a record gate taking across the year. We were budgeting for a record membership and we have hit targets already before a ball was even kicked.
"At the team announcement at the game last Thursday Sonny got the biggest cheer. I've been quoted before as saying he is like the David Beckham of the Southern Hemisphere. He has got it all going in terms of looks and physique and talent and personality."
While the Roosters are set to enjoy a significant return on Williams' reported A$550,000 ($687,693) salary, the Sydney club won't be the only one cashing in. Crowds at Roosters away matches are tipped to rise by about 6000 thanks to the SBW factor.
The Warriors lobbied the NRL hard to face the Roosters in their first home match of the season at Eden Park. The Roosters have strong Kiwi connections throughout their squad, but Williams is the major drawcard.
Warriors co-owner Sir Owen Glenn famously dismissed Williams as a "show pony" at his first press conference after buying into the club, but that doesn't mean it is above using his image to drive interest in Saturday's match. Despite being in the midst of a record eight-match losing slump, the Warriors hope for a crowd of about 30,000 on Saturday. If they get it, they are likely to have Williams to thank for a good chunk of it.
Quantifying the SBW effect is difficult, says long-serving Chiefs marketing manager Sean Austin. The Chiefs enjoyed a huge boost in support last year with Williams in the ranks. They rebounded from two poor seasons to win the Super rugby.
One thing Austin was certain of is that Williams took his role as a club figurehead seriously. The collective contract rugby players sign with their employers dictates the use of their image rights. Although Williams refuses to endorse alcohol or gambling because of his Muslim faith, he would frequently waive his rights under the collective so the Chiefs could use him for promotional purposes.
"He would be one of the most professional rugby players I have ever dealt with," Austin said. "What he does really well is engage with fans. And as far as I could see it was very genuine. Whether it was kids or adults, he always made a real effort to connect with them. He would always be one of the last to leave a signing session because of the interest in him. That really helps in terms of having such a high-profile star who made himself really accessible.
"He was quite prepared to go above and beyond. I know I sound like a cheerleader but a lot of the things I saw first hand certainly contradict some of the public's perceptions of Sonny."
Austin's view of Williams is at odds with the self-absorbed mercenary often portrayed in the media. On his first day at the Chiefs, Williams discharged his significant media responsibilities before spending his afternoon getting to know a group of sick or vulnerable children.
Another time, Austin was driving through Hamilton when he came across Williams playing the good Samaritan. "An old lady had broken down on the other side of the roundabout. Sonny had pulled his car over, got out and pushed her across the roundabout. There are plenty of other examples like that which for me epitomise his attitude."
But Williams' time with Canterbury and the Crusaders is less fondly remembered by the staff there, while after his 2008 walkout from the Bulldogs Williams was voted Australia's most hated man - ahead of Osama Bin Laden.
And over-exposure is a risk. Australian TV network Channel Nine's innovation of dubbing a Williams audio track of his thoughts as he ran on to the field for his comeback was a step too far for many. It also invited ridicule when he wasn't able to live up to his own expectations.
"The Sonny Bill factor is hard to control, particularly with the media over here," Helliar admitted. "The media interest and pick-up over Sonny has been enormous. We have used him extensively but at the same time we have tried to shield him a little bit as well so he can integrate into the team, get his head right and get into playing football again. It has been an interesting process."
Former Kiwis teammate Benji Marshall probably summed it up best when assessing Williams' comeback.
"The Roosters signed him to do a job - not only on the field," Marshall wrote in his Sydney Morning Herald column. "If you look at the crowd at Allianz Stadium, and the people who tuned into their televisions, his return was a success."
Females flock to Williams
The crowd dynamic changed at the Chiefs Super rugby franchise in 2012. Fathers and sons who had attended games for years in blissful peace all of a sudden found themselves accompanied by wives, sisters and girlfriends.
The demise of the classic Kiwi male bonding outing was almost certainly down to one thing - the SBW effect.
Wherever he goes, the sporting phenomenon that is Sonny Bill Williams puts extra bums on seats, many seemingly more shapely than those of traditional rugby fans.
"We were coming off a tough couple of years and there is no doubt that he heightened interest around our brand," said Chiefs marketing manager Sean Austin. "We got a lot more attention from the media; he certainly brings that. And we certainly did notice higher interest from the female market. We had members saying they had been coming for years as father and sons and suddenly the mum and the daughter wanted to come too."
Warriors chief executive Wayne Scurrah agreed Williams possesses a wider appeal than many football players. "Even with his shirt on he is a great-looking bloke," Scurrah said. "He looks the part. He talks well. He could probably have a modelling career next if he wanted to. I'd imagine females would love to go and see Sonny compete at whatever sport he chooses to compete in."
Scurrah will be hoping that translates into a big attendance at Eden Park on Saturday. By yesterday, 24,000 tickets had been pre-sold for the match between the Warriors and Roosters. Scurrah said he was hoping for a crowd of 30,000.
The SBW effect
18,000: The average match attendance the Sydney Roosters expect now SBW is on the squad - up from 14,000
25%: The rise in club memberships sold over the number for 20126000The average number of extra fans Williams is tipped to attract to away matches
A$3m: The extra revenue the 15 rival NRL clubs are forecast to get now Williams is back playing league
35,952: The crowd who attended Williams' return match against the Rabbitohs last Thursday night was the largest ever for a round-one NRL match in Sydney. It attracted the largest viewership in Sydney for an opening-round match since ratings began in 2001
7%: The increase on the previous year's corresponding match between the Knights and Dragons. More than 1.37 million viewers across Australia watched the Rabbitohs v Roosters clash.
3: The number of sports Williams has won titles in. He won an NRL premiership with the Bulldogs, a Super rugby title with the Chiefs and the Rugby World Cup with the All Blacks, and is the reigning New Zealand and WBA International heavyweight boxing champion.
