In a move that courted controversy, the classy wicketkeeper-batsman crossed the Tasman in January to play for New South Wales Blues in the final of the Australian domestic twenty/20 competition instead of turning out for Otago in a one-day round-robin match.
By switching allegiances, McCullum qualified to play for the Blues in the lucrative Champions League in India in September-October, where the winner will pick up a cheque for $6 million.
But with Otago expected to be invited to compete in the tournament following its twenty/20 title win, McCullum suddenly has two options - three, if his Indian Premier League team, the Kolkata Knightriders, also qualifies.
It contracts him for a staggering $950,000 and is likely to insist on having first dibs.
There is no guarantee Otago will be invited although the Wikipedia website has already included Otago alongside the other sides to qualify, and the official Champions League website carried an Otago Daily Times story on the Volts' twenty/20 title win.
That may suggest Otago's invitation is a mere formality.
McCullum could not be reached for comment yesterday, but in a column he wrote for the Otago Daily Times on January 27, he said "I am an Otago boy, and feel an immense amount of pride and satisfaction whenever I play for the blue and golds".
But he also pointed out that the international cricket landscape had changed and the opportunities on offer were hard to ignore.
The way McCullum plays, those opportunities must be flooding in.
In the Indian Premier League (IPL) opener, he pummelled 158 off 73 balls, and last year he blasted 170 off 108 balls to help Otago claim its first national banner in 20 years.
However, Otago Cricket chief executive Ross Dykes believes McCullum will throw his hat in with Otago instead of New South Wales if Kolkata fails to qualify.
"I have not asked him, but I've got a fairly good idea of where his loyalties would lie and they would lie here," Dykes said.
McCullum was born and raised in Dunedin and went to Kings High School.
He made his debut for Otago the same year his older brother, Nathan, made his first appearance for the Volts.
Of course, if McCullum does play for a team other than Otago at the Champions League there is a sweetener for New Zealand Cricket.
The national body will be paid a transfer fee of US$200,000.
Dykes said it was unclear how much of that money would filter down to the associations and "what is a fair and equitable way to slice the pie up".
