Toronto have never made the finals in their six seasons in the MLS and would require a huge improvement to do so. In 2012, they finished 29 points out of the play-offs and 12 points adrift of the next side on the table.
While they should improve under Nelsen and new general manager Kevin Payne, the other clubs won't stand still either. A more likely outcome is consolidation and respectability.
If they make the final cut, it is hard to see the Canadian side going deep into the play-offs. The regular season finishes on October 26, three weeks before the first intercontinental play-off on November 14, which is played within a Fifa window.
If their season is over, it is hard to imagine the club standing in his way, especially with the kudos and exposure for Toronto FC. Nelsen might enjoy the chance to do something unique and there is a pertinent local example. NBA legend Steve Nash is currently general manager of the Canadian basketball team but continues to turn out for the LA Lakers.
Whatever unfolds, the scale of the November clashes cannot be underestimated.
"If we make it through [past March], the two matches in November will arguably be the biggest games in New Zealand football history," McKavanagh says. "To make it to successive World Cups would be absolutely huge and the benefits would go well beyond the financial [NZF would expect a windfall of at least $12 million]."
"I hope he can still play, the country will hope he can still play," says fellow All White Ivan Vicelich. "We'll just have to wait and see."
Nelsen would earn his 50th cap if he was available for the March 22 clash versus New Caledonia but it seems a long shot, given his Queens Park Rangers commitments and the fact that Toronto have games on March 16 and 30. It may be pragmatic to shelve that and focus instead on netting Nelsen for November.
However, it all rests with Nelsen, who may feel he has done enough and want to go out with the legacy of his 2010 heroics in South Africa.
Nelsen also sets high personal standards and won't want to compromise those. Fans can only hope that he has the will - and NZF finds a way - for him to be present in November, as anchoring the team to a second qualification would be a fantastic farewell gift.
Meanwhile, OFC has confirmed the final qualifying games will be played as scheduled, with the All Whites facing New Caledonia on March 22 and the Solomons four days later.
There was thought given to New Zealand hosting the cash-strapped Solomon Islands here, giving the visitors a better payday. It was also suggested that the match might be delayed by some months, allowing the All Whites to focus on New Caledonia. However, OFC decided to stick with the original draw on the grounds of fairness to all.