Sam said a difficult year has led to him being concerned for his mental health, which in turn is leading him to step away from football at this time.
Sam was drafted by the St. Louis Rams in the seventh round of the 2014 NFL draft, making him the first openly gay player to enter the league.
Sam, a former first-team All-American and SEC Defensive Player of the Year at Missouri, was waived by the Rams at the end of training camp last season. He spent part of 2014 on the Dallas Cowboys' practice squad.
In May, Sam signed a two-year contract with Montreal, making him the first openly gay player in the CFL. He made his Alouettes regular season debut on Aug. 7 after sitting out the team's first five games.
- Rohan Nadkarni