Nick Robertson has not been offered a contract by Brisbane for the 2020 season.
Robertson departs having played 73 games for the Lions with his most recent appearance coming in the semi-final loss to GWS.
The 24-year-old defender struggled for senior opportunities in 2019 playing just five AFL games.
"Robbo has always given 100 per cent at everything he has done; training, preparation, the way he plays," GM of Football David Noble told lions.com.au.
"I am hopeful another club would provide him with another opportunity as a delisted free agent.
"We thank him for his time at the Lions. It's always hard saying goodbye to good people."
Robertson went at pick No.34 in the 2013 National Draft.