Gillon McLachlan is set to be announced as the AFL’s new chief executive with Andrew Demetriou poised to leave the post earlier than expected.

AFL Commission chairman Mike Fitzpatrick will hold a media conference at 11am (AEST) at AFL House in Melbourne to announce McLachlan’s appointment.

It’s also understood Demetriou, who was to end an 11-year stint as chief at the end of the season, will now depart in the first week of June.

Demetriou’s long-time deputy, McLachlan is believed to have beaten challenges for the top job from AFL club bosses Brian Cook and Brendon Gale.

He has long been regarded as the most likely successor and knocked back the NRL’s chief executive role in 2012 before Dave Smith was appointed to that job.

South Australian-born McLachlan joined the AFL with Demetriou in 2000, rising to the executive three years later and has been groomed as Demetriou’s successor for three years.

Unlike Demetriou, McLachlan has not played the game at the highest level but joined the league as an amateur footballer with University Blues.

He has played key roles in the major AFL projects of recent years including the addition of the Gold Coast Suns and GWS Giants to the competition, and setting up the AFL media department and broadcast deals.