The decision by former agriculture minister Nathan Guy to retire from politics at the next election was a fortuitous one for National leader Simon Bridges.
It gave Bridges an unexpected chance to rejuvenate his line-up again but it also gave him a chance to right a wrong in his previous reshuffle last month.
Like Amy Adams in the June reshuffle, Nathan Guy's departure meant he had to drop his agriculture responsibility now, opening it up for competition.
Assuming Bridges wanted someone with a connection to agriculture and someone with political experience, the pool he had to choose from included Taranaki-King Country MP and farmer Barbara Kuriger, Bay of Plenty MP and former Zespri and Fonterra executive Todd Muller, Hamilton East MP and farmer David Bennett Rangitikei MP and farmer Ian McKelvie, and Kaikoura MP and winegrower Stuart Smith.
Kuriger could have handled it well but she is too valuable as chief Opposition whip (the post previously held by Jami-Lee Ross) and she is virtually assured of a cabinet seat in any National Government.
Todd Muller got the big promotion today, moving from climate change spokesman to agriculture.
(It would be as unthinkable to hold both portfolios at the same time).
The sheer dominance of the climate change issue in public discourse meant that many people saw it as a sideways shift at best, or even a demotion Muller.
However it was a vacancy in the National Party, not in the Green Party and there is no more important constituency in National that the rural sector.
Muller made his name as an agri-business executive but he was raised on his grandparents' dairy farm in Pukekohe as a young child and then moved with his family to a kiwifruit orchard.
Agriculture is a portfolio that would never sit outside cabinet either, and so Muller got not only a promotion in portfolios in the reshuffle but a huge jump in caucus rankings from number 31 to number 17.
It was not before time.
Bridges snubbed Muller in last month's reshuffle.
He left him at No 31. That raised eyebrows and reflected badly on Bridges.
Chris Bishop, the same intake as Muller, was promoted from No 35 to no 16, a deserved promotion.
Gerry Brownlee got back Foreign Affairs, as he should have got as former Foreign Minister when Bridges first won the leadership.
But there was nothing for one of the most talented members of caucus. It was decision that made Bridges look churlish, reluctant to promote talent and possibly paranoid about his leadership.
Muller has always been seen as potential cabinet material, if not a potential leader since being elected in 2014.
He has occasionally been subject to speculation as potential deputy to Judith Collins and maybe he should have been faster to deny that prospect.
He applied himself well to developing the Zero Carbon Bill with Greens co-leader and Climate Change Minister James Shaw.
But in Bridges, Muller may have had a hard taskmaster. After all, Bridges was also extremely familiar with the subject as the former Climate Change Minister who signed New Zealand up to the Paris Accord. They worked together with Shaw but in Bridges' eyes, Muller may not have added that much value.
Muller and Bridges have a historic rivalry, both having lived in Tauranga in the early 2000s and both with an eye to the Tauranga seat, which was held by New Zealand First leader Winston Peters until 2005 when Bob Clarkson ousted him.
Muller did not seek selection in 2008 when Clarkson bowed out because he had relatively recently started with a new firm. Bridges won selection and the seat in 2008, keeping Peters out of the seat for the second time.
Muller won selection in neighbouring seat Bay of Plenty in 2014 when former Health Minister Tony Ryall decided to retire from politics.
Circumstances forced Bridges to promote Muller to agriculture rather than generosity or magnanimity.
No matter how he got the job, Muller now has to prove he is worthy of it.