For the first time since his celebrated conversion to rugby Sonny Bill Williams is practically a bit part player as his Crusaders debut is destined to be overshadowed by the tragic events in his adopted home city.

Williams readily accepted his role in the greater scheme of things in Christchurch this week when tempering his enthusiasm for a first crack at Super rugby with concern for the inhabitants of earthquake-ravaged Christchurch.

After absorbing more than a week's worth of heroic tales in the aftermath of last Tuesday's 6.3-magnitude quake the 25-year-old is not expecting to be a miracle worker against the Waratahs at Nelson's Trafalgar Park on Friday night, his first rugby experience since the All Blacks' Grand Slam-clinching Test at Cardiff on November 28.

A leg injury saw Williams substituted nine minutes after halftime against Wales; since then his multi-faceted sporting career has been confined to the third fight of his unbeaten professional boxing career on January 29.

After an intensive training session at the Crusaders' temporary home at Lincoln College on Wednesday, Williams was not setting his expectations too high ahead of resuming his midfield combination with Robbie Fruean.

"I'm not sure," a guarded Williams said when asked whether he expected to feature throughout the third round contest.

"I will push hard for as many minutes as I can. If the body's feeling good then it's feeling good ... if not, well it's a long year."

It has also been a long -- and challenging -- interlude for the Crusaders since their opening round to the Blues -- and naturally the earthquake has loomed large in the squad's psyche.

Williams was in a central city pool when ripples transformed into waves; his central city apartment is also off limits inside the "four avenues" cordon - not that the four-cap All Black has been inconvenienced.

"I'm not going to stand here and say I know what (people in Christchurch) are going through because I did not lose a loved one," he said.

"I don't think too many of the (Crusaders) boys lives are back to normal but there are a lot of people worse off than us down here.

"I count myself lucky and I know the rest of the boys do too."

Although the Canterbury provincial team and the Crusaders are only conduits for Williams to achieve his goal of competing at this year's World Cup, the Aucklander said the experience of two earthquakes and the Pike River mining disaster fostered an affinity with the region.

And he has been in Canterbury long enough to realise the significance of the outcome on Friday at Trafalgar Park.

"This is definitely a game for the Canterbury people and hopefully it will take their minds off what has been happening around them for 80 minutes," he said.

"We have to go back to normality and be the big, strong rugby players that we are."

Now staying with a mate in a secure part of Christchurch, Williams revealed he resisted demands from his mother Lee to join her in Auckland.

"I got the texts about the cheap flights, she was dropping big hints but I've got a few things I need to sort out down here. Playing some good rugby is one of them."

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