Geelong premiership defender Jake Kolodjashnij is heading towards a likely retirement, with a formal announcement expected within the next week.

The decision will bring a sad end to his AFL career, two months after the concussion clause in his contract was first revealed.

WATCH THE VIDEO ABOVE: Kolodjashnij retirement imminent after concussion contract investigation

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Kolodjashnij signed a “voluntary assumption of risk” outside of the AFL’s standard playing contract, which required the defender to assume legal responsibility for any future head trauma.

The 31-year-old has played 35 games since signing the document in 2024, but just 11 this year and none since Round 18 when news of the side deal emerged.

The Cats were eventually handed a massive $140,000 fine for failing to lodge the clause with the AFL, but were spared any additional punishment.

There was, however, no clarity on the future of Kolodjashnij.

Jake Kolodjashnij is set to be forced into retirement. Credit: Getty

His initial meeting with the concussion panel back in 2024 returned an amber reading, which resulted in Geelong adding the waiver in his contract.

It’s understood he has underwent additional testing in the past month, but failed to receive clearance to continue his career.

7NEWS chief AFL reporter Mitch Cleary provided more detail on The Agenda Setters.

“Initial tests point to Kolodjashnij being retired out of the AFL. Those extra tests have come back and Geelong didn’t want to proceed,” he said.

Tom Morris said there were two ways to look at the “unfortunate” situation.

“The amber return from the panel allowed him to play another two years of his career, but it also brought an to his career because once it got out, he was done,” he said.

“Very unfortunate because he felt he could play up until a few weeks ago.”

Cleary also said that going forward the concussion panel will likely return a yes or no answer, rather than the amber reading.

Morris added: “At the very least if a club gets back an orange or amber reading for any player there needs to be a path forward dictated by the AFL and medical doctors, they can’t just wash their hands of it and tell the clubs to sort it out or else what we saw with the waives might happen again.”

Kolodjashnij finishes his career with 209 games, including the 2022 premiership win over Sydney.

He joins his twin brother Kade in being forced into premature retirement due to concussions.

Kade played 80 games with Gold Coast and Melbourne before his career was cut short at the end of 2020.