COLLINGWOOD defender Tom Langdon has called time early on his AFL career due to a degenerative knee injury.

It comes as long-time Pies football boss Geoff Walsh announced he will step away from the game after almost four decades in key administrative roles.

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Langdon, 26, had been in talks with the Pies for several months about walking away from the final year of his contract for 2021 and made the decision in recent days.   

Langdon will be removed from the Pies' list as part of the latest list lodgement on Monday, leaving the Pies with 34 contracted players ahead of the NAB AFL Draft. 

Langdon played 89 games for the Pies across six seasons – the last coming in round nine, 2019 before he succumbed to chronic cartilage damage in his knee. 

He spoke candidly in March about his struggle to return to the field, and while not playing AFL this season, featured in a handful of Pies scratch matches through the middle stages of the year.

"(Retirement is) an option, absolutely," Langdon told Channel Seven. 

"It's been a tough eight months, to be honest, to wrap my head around that being an option, being 25 and young and reasonably healthy. 

"That's been a hard reality to come to terms with but at this stage a lot of water to go under the bridge and it is feeling quite good so I'm feeling pretty optimistic. 

"The club's been super supportive the whole time, they've never pushed me. We're both trying our hardest at the moment to get up and play again because obviously I love Collingwood and I love playing AFL football. That's the goal. I guess we're on track to a degree." 

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Coach Nathan Buckley told AFL.com.au in February the Pies would be leaving no stone unturned in Langdon's recovery.

Langdon will be remembered most for his fearless defending and his performance in the Pies' losing 2018 Grand Final to West Coast where he polled in the Norm Smith Medal. 

He was drafted as a 19-year-old from the Sandringham Dragons at pick No.65 in the 2013 NAB AFL Draft. 

Langdon knocked back a lucrative deal to join Sydney at the end of 2018 to re-sign on a three-year contract with the Pies.

Meanwhile, Walsh will officially retire from his post in December in what was his second stint at the Pies.

The 64-year-old started his administration career at Fitzroy in 1985 before moving to Carlton as recruiting manager in 1986. From 1994-2001 he was North Melbourne's head of football before he was promoted to CEO for 2002-2006.

Following that he joined Collingwood as head of football until, returned to North Melbourne in the same role for four years before re-joining the Pies ahead of the 2017 season.

"I have been contemplating this for some time and as one of my old coaches once put it, the moment you start thinking about retirement is the time to finish," Walsh said.

"I am ready and the time for Collingwood is also right. I will thank personally the many people I need to but I would like to acknowledge the game for the rich experiences, friendships and professional rewards I have been lucky enough to enjoy."

"It was a privilege to serve the game."

Walsh's departure coincides with one of the club's busiest ever off-seasons – headlined by the forced departures of contracted trio Adam Treloar, Jaidyn Stephenson and Tom Phillips due to salary cap pressures.

The Pies last week delisted Rupert Wills and Flynn Appleby after coming to an arrangement with Dayne Beams on the final two years of his contract. 

With Jack Madgen and Brody Mihocek promoted to the senior list, it leaves the Pies with four rookies for next year – John Noble and Mark Keane (Category A), and Anton Tohill and Tom Wilson (Category B).

Under new list constraints, each club must have a minimum of 37 (minimum 36 senior listed) and no more than 44 players for 2021.

Unless the Pies add further players to their senior list in the second delisted free agency window that runs Tuesday-Wednesday, they will need to take at least six players in the NAB AFL Draft.

The Pies currently hold picks 14, 16, 65, 70, 75 and 92 for this year's NAB AFL Draft and have placed their 2021 first-round pick on the table for a possible transaction with another club for an early pick this year.