Geelong are expected to announce two-time premiership coach Mark Thompson will quit the AFL club to join Essendon at a press conference on Tuesday.
Thompson is reportedly set to move into a role as director of coaching with the Bombers, who he formerly captained.
It would be a huge success for Essendon, who earlier on Tuesday confirmed another former skipper, James Hird, will coach them for the next four seasons.
But they refused to confirm that Thompson would also be part of a revamped coaching panel.
The Cats have also stayed silent on the speculation, but chief executive Brian Cook and football manager Neil Balme are due to address media at 3pm (AEST) Tuesday.
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Thompson has coached Geelong since 2000, leading them to the 2007 and 2009 premierships, and is contracted for next year.
Assistant coach Brenton Sanderson and former Cats assistant Ken Hinkley, now a senior assistant with Gold Coast, will be the two frontrunners to replace him.
Hinkley came close last year to winning the Richmond coaching job, which instead went to Damien Hardwick, while Sanderson has been publicly touted by Thompson as ready to take on a senior role.
Sanderson was initially in the running for the Port Adelaide job, which went to Matthew Primus, before pulling out part way through the selection process.
The Cats will need to act quickly, given they face some important decisions on their playing list, ahead of trade week, which starts next Tuesday.
They are set to lose their star player, Gary Ablett, who is expected to announce in the next few days he is joining Gold Coast.
Geelong need to decide whether to enter a rebuilding mode, with their era of dominance seemingly over after their crushing preliminary final defeat to Collingwood.
Thompson's expected resignation would fly in the face of the attitude he had expressed towards Ablett's potential departure earlier this season.
The coach has said he could not understand the superstar midfielder wanting to leave for a huge Gold Coast contract, expressing his admiration for the loyalty of fellow midfielder Joel Selwood, who re-signed with the Cats.
