MacGregor and St Mirren counterpart Stewart Gilmour voted against proposals to change the league format earlier this month in a meeting where the 10 other Scottish Premier League chairmen backed the proposed three divisions of 12, 12, 18.
But MacGregor insists there does need to be a different format from the current system.
"Change isn't a necessity, it's inevitable. We've got to find the right formula," MacGregor said.
"There is a meeting next week and I really believe that something will come back to the table that everyone can buy into.
"I wouldn't be speaking as optimistically as I am if I didn't believe something would happen.
"I think it could be in place for next season. The board met and are looking at alternatives."