Doncaster has been examining league structures across Europe after his idea for a 16-team division was welcomed by many SPL managers. And he is coming to the conclusion that changing more of the participants could revitalise the league.
He said: "We have had discussions with six leagues in Europe so far and the biggest lesson learned is that refreshment comes through increased promotion and relegation. In Scotland we have the lowest relegation out of anywhere in Europe, just one team from 12, and that's something we have to address.
"There is definitely an appetite for change in the Scottish game just now. We have seen that through direct feedback from fans, comments from managers and through media coverage."
Doncaster, who reiterated that any changes would have to make commercial sense, added: "Everything is firmly in the melting pot but we hope to take things forward at the next SPL board meeting in May, and then there's the general meeting in June.
"Ultimately it's for the clubs to decide whether they want to embrace change."