Knights turns 26 on Wednesday and has found opportunities hard to come by under Brenton Sanderson, managing only five games in 2012.
He played 96 games in eight seasons with the Crows, with his best year coming in 2009 - when he kicked 43 goals from 20 matches.
Injury blighted his 2010 campaign, but he hit back well in 2011 and seemed to enjoy a shift into the middle, before again being struck down by injury.
The Victorian leaves as an unrestricted free agent, meaning he is able to join any club of his choice, with the AFL to decide what draft pick the Crows will receive in compensation.
Crows football manager Phil Harper said the club wished Knights well.
"It has been a difficult year for Chris as he has struggled to get a regular game with our team," Harper said.
"However, his effort to remain positive, upbeat and ready to take his next opportunity has been a credit to his character."The club wishes Chris all the best in his future football endeavours and beyond his football career, when he will always be welcome as a past Adelaide Football Club player," he said.