Murphy was concussed by a high collision early in last year's grand final and hasn't played since, with the defender opting out of match simulation training in February.

The 24-year-old Murphy, who had suffered multiple concussions prior to and during his AFL career, consulted with the AFL's concussion panel on Saturday and the decision was made for him to "medically retire" from football.

He informed his teammates on Tuesday morning.

"It's been a massive journey. It's been six-and-a-half years now and the last few months have been really tough but I was guided by medical advice that this was the right decision for me," Murphy told reporters.

"I'm really grateful that it's probably come to this because they're the professionals and I just have to trust their opinion."

Murphy is the second player this year to be forced into retirement following a concussion suffered in last year's finals series.

Melbourne midfielder Angus Brayshaw called time in February after he was knocked out in an attempted smother from Murphy's Collingwood teammate Brayden Maynard in their 2023 qualifying final.

In last year's grand final triumph, Murphy was concussed in a first quarter collision with Brisbane's Lincoln McCarthy, when his head hit the Lion's shoulder, and he was subsequently substituted out of the game.

He was examined by the league's concussion panel and was ultimately given the green light last December to resume playing.

But he didn't play again.

"This has always been a week-to-week process and just how I'm going and how I'm feeling each week," Murphy said.

"You have some good weeks and you have some bad weeks.

"So that continued probably (in terms of) symptoms and that was ultimately why they thought it was the best decision for me to retire at this point in time.

"I'm definitely accepting (of the decision). These guys are the professionals in this space.

"There's so much unknown in this area that you just really have to trust the professionals. I'm guided by their decision and really happy they've made this decision."

The courageous defender had tried to adjust parts of his game to protect himself better.

"There were things we altered but ultimately we did what we could, but the medical decided it for me," he said.

Drafted in 2017, key defender Murphy played 57 games, including 24 in his breakout campaign last season as a crucial part of Collingwood's backline.

Club football boss Brendon Bolton hailed Murphy's maturity and said the Magpies were "really open-minded" about the possibility of him remaining in an off-field role.

Murphy is part-owner of a cafe, while the former gun junior cricketer for Victoria and Australia hasn't yet considered whether he'll return to that sport.

"I have been joking around that I'll be the first guy to win an AFL premiership and open the batting on Boxing Day for Australia," he said with a laugh.

Australian Associated Press