Weep not All Blacks fans, skipper Richie McCaw says he's pretty sure tomorrow night's Bledisloe II test against the Wallabies won't be the last we see of Sonny Bill Williams in the famous black jersey.

The triple-sport superstar tomorrow night ends - for now -- what will be an all-too-brief 19-test career with the All Blacks that lasted just two years. He agreed to play the opening two Bledisloes of the year to help fill the void created by the injury to centre Conrad Smith.

But after tomorrow Williams is off, already having decided to turn his back on the New Zealand game to head, first, for a short rugby stint in Japan before taking up a "handshake" deal to return to the National Rugby League, said to be with the Sydney Roosters.

So tomorrow night's test at a sold-out Eden Park is a farewell of sorts for a player whose skills and physicality have impacted on the XV-man game like no other since Jonah Lomu unleashed his wrecking ball impression on the wing.

With Williams just starting to mature into a legitimate test rugby star, most New Zealand rugby fans regard it as a great shame that he is turning his back on the game right when he appears to have come of age.

McCaw's name can be added to that list.

"He's just showing how much of a force on the international stage he is in rugby," said McCaw during today's captain's run at a sun-drenched Eden Park. "I guess from our point of view it's been great to have had him last week and again tomorrow. But he's always said you never know what's around the corner for him, so he may well be back.

"It's disappointing not to have him [for the rest of the Rugby Championship] but that's the way it is."

"May well be back"... it was only fair to seek some clarification from the World Cup-winning skipper on that comment. Would he be surprised to see Williams back playing for the All Blacks in the not-too-distant future?

"No, I probably wouldn't be surprised," said the test centurion with a grin that suggested he may well know something the rest of us are not privy to.

McCaw said there had been no special words to his team-mates this week from Williams, who has won the Ranfurly Shield, played in a Grand Slam and added the NPC, Super Rugby and World Cup titles in his short time in rugby. Nor did he expect there to be.

"He's very much enjoying the chance to go out and play and seems pretty excited. You don't get too carried away with personal things, but he's pretty keen to play well in his last test and we've got to make sure it's a good one for him."

But the All Blacks' motivation this week, confirmed McCaw, was all about dealing with what they expected would be a significant Wallaby backlash as Robbie Deans' men look to keep their Bledisloe and Championship hopes alive.

"There's a realisation we've got quite a few areas from last week we need to improve on, and because of that the guys have gone about their work pretty well. If we're serious about performing every week we've got to look at the performance. It was only in patches, and we want to be better than that.

"I'll be disappointed if we don't improve significantly."

McCaw said both teams had their "challenges" after last week's 27-19 victory by the All Blacks in Sydney that highlighted shortcomings across the board. But he reckoned the mounting pressure on Deans across the Tasman would see a pretty significant Wallaby response.

"Sometimes that's when he's been at his best, when the pressure comes on," said McCaw of his old Crusaders coach. "There's no doubt they'll be ready to go. A week is a long time in this sport, and we've seen on many occasions over the last wee while where what you expect doesn't happen because a team's on edge.

"We've got to make sure our guys realise just because we got home on the scoreboard [last week] it doesn't mean much when kickoff comes tomorrow night."

An All Blacks win would extend to 10 years the period since Australia last held the Bledisloe. It would also extend a 26-year, 13-test winning streak against the Wallabies at Eden Park, which included defeat in last year's World Cup semifinal.

The test, which will be in front of a full house of around 50,000, will see all fans given red noses to mark the fundraising initiative for the All Blacks' official charity, Cure Kids.

- © Fairfax NZ News