"The theory is that if he sells his shares, there's a new ownership structure and maybe things will be more peaceable."
The presence of Prokhorov, who famously ran unsuccessfully against Vladimir Putin for the Russian presidency, adds an interesting political dynamic to the deal. Mazepin's support was welcomed by Ostling.
"Mazepin is an interesting character in this dynamic because he's a fertilizer guy, so the combination is a very attractive one," Ostling said.
China Investment Corp (CIC), China's sovereign wealth fund, bought a 12.5 percent stake for an undisclosed sum in Uralkali in September. China is already one of the world's biggest importers of the commodity.
Earlier this year, Uralkali ended its commercial partnership with Belarusian state-owned Belaruskali, its partner in Belarusian Potash Co (BPC). The joint venture controlled around 40 percent of the global market and, because of this share, had a great deal of influence on the price of potash.
(Read more: Potash powerhouse crumbles)
"Our partner was selling stuff off the back of the truck," Ostling told CNBC.
"We came to a point where the relationship really wasn't good, and we tried to fix it and we couldn't."
Following the break-up of the cartel, Vladislav Baumgertner, Uralkali's chief executive, was arrested in Belarus in August following a meeting with Belaruskali, and has languished in jail or house arrest since then.
He has not been allowed to speak to his Russian lawyer, and his Belarussian lawyers are not allowed to communicate directly with Uralkali.
"We've seen nothing from anyone to suggest that Vladislav is guilty of anything," Ostling said.
The overall market for potash is worth around $20 billion annually and around 50 million tons are produced every year, most of it in Canada, Russia and Belarus. Large swings in its price can affect the price of other commodities like corn and sugar - and consequently could have an impact on global food prices.
The squabbles have sent the price of potash tumbling, down 10-15 percent on the start of the year. Governments like India, Brazil and China negotiate several big deals a year, and early signs are that they will be pitching for lower prices again in the next big round of buying, for the first half of next year. Belarus has announced that it is planning to cut the price of potash exports to $300 a tonne in 2014.
As a result, Uralkali's revenues have tumbled. Prokhorov's first job will probably be to restore some kind of relationship with the Belarussians, and get back his chief executive. This is not going to be the last chapter in the potash saga.
Follow Catherine on Twitter: @cboylecnbc
Correction: The headline has been updated to reflect that the team is called the Brooklyn Nets.