Former Hawthorn and Sydney defender Kaiden Brand has been forced to step away from football "indefinitely" amid an ongoing battle with concussion.

Brand sustained a serious head knock while playing with SANFL club West Adelaide in 2022, with the 29-year-old's last game for the Bloods coming in July of that year.

The South Australian returned to his former club at the end of 2021 after his AFL career with the Hawks and Swans came to an end.

After 13 matches for the Bloods in his return season, Brand's year was cut short as a result of concussion.

The key defender was voted in as captain of the club for 2023 but wouldn't be cleared for a return, instead helping the club in various roles, including matchday runner.

A "small recent setback" and further consultation has led Brand to step away from football in what he has labelled "one of the hardest things I've had to do".

"I am deeply saddened to have to inform you that due to my ongoing concussion recovery I have had to make the tough decision to step away from playing indefinitely," Brand wrote in a letter to West Adelaide supporters.

"It is not the outcome I was hoping for however after a small recent setback and speaking with doctors and my family it is the right decision in attempt to return to full health long term.

MELBOURNE, AUSTRALIA - JANUARY 20: Kaiden Brand of the Hawks in action during a Hawthorn Hawks AFL press conference and training session at Waverley Park on January 20, 2017 in Melbourne, Australia. (Photo by Michael Willson/AFL Media/Getty Images)

"I have left no stone unturned in my pursuit to return to playing and while this is the right decision for my long term health it has been one of the hardest things I've had to do.

"It has been a tough eighteen months and I want to thank everyone involved with West Adelaide as I have felt supported all the way through and I appreciate the patience that has been shown while I have been attempting to return to playing.

"Being a captain of this football club is one of the greatest honours and privileges I have had through my football career and it breaks my heart that I haven't been able to contribute more to the role on field.

"Coming back to the football club two years ago I wasn't completely sure what to expect after being away for so long but it has become a second home to me again and while my journey hasn't been the easiest over the last eighteen months I have always been able to come to the club and feel the love and support from everyone and it's something that I don't take lightly or for granted.

"I remain fully committed to the football club and helping our team continue to develop and you will certainly still see my face around the place, I guess the only thing that will change is the hope of me pulling on the red and black in 2024.

"I'm extremely optimistic about what we can achieve as a group and with Harts (West Adelaide coach Adam Hartlett) steering the ship I know we are heading in the right direction."

Brand played 43 games for Hawthorn after being drafted out of West Adelaide in 2012, making his debut in 2016 to claim the Best First Year Player Award at the Hawks that year.

Sydney signed Brand as a delisted free agent in 2019, with the Berri product going on to play five games for the Swans across two seasons.

Brand would win a VFL premiership with Box Hill in 2018 and earned representative honours with the SANFL for the 2022 State Game against Western Australia.