(Reuters) - Michael Sam, who last year became the first openly gay player drafted by a National Football League team, said on Friday he was stepping away from football, citing concerns over his mental health.
The Canadian Football League's Montreal Alouettes, with whom he signed a contract in May, said on its team website that Sam had left the team for personal reasons and as a result had been placed on the team's suspended list.
"The last 12 months have been very difficult for me, to the point where I became concerned with my mental health," Sam wrote on Twitter. "Because of this I am going to step away from the game at this time."
"Thank you all for your understanding and support," he added.
Sam also thanked the Alouettes, and said he hoped to be back on the field soon. The defensive lineman was suspended by the Alouettes in June after he left the team's training camp for unexplained personal reasons.
The National Football League's St. Louis Rams selected Sam in the seventh round of the 2014 draft but waived him in the final round of cuts. He was picked up by the Dallas Cowboys but they released him from their practice squad in October.
Sam was the Southeastern Conference Defensive Player of the Year as a senior at the University of Missouri before graduating in December 2013.
The following February, before the NFL Draft, he announced he was gay.
ESPN reported that Sam agreed to a two-year deal with the Alouettes this summer. It also reported that he sat out the team's first five games and that he failed to record a tackle during his team debut on August 7.
Sam's supporters have said that his sexuality is irrelevant to his performance and have dismissed suggestions that an openly gay player would be a distraction for a professional football team.
Reporting by Eric M. Johnson in Seattle; Editing by Will Dunham and Ken Wills