Michael Sam is worried about his mental state ... so he's leaving football -- again -- one week after he became the first openly gay player in a professional game.
Sam announced he's quitting the CFL's Montreal Alouettes because "The last 12 months have been very difficult for me, to the point where I became concerned with mental health."
He thanked the Alouettes for giving him a chance to return to football ... after he was cut from 2 NFL teams. He'd also had issues while playing in Canada, and flirted with leaving before.
Oddly, he said he hopes to be "back on the field soon."
It seems unlikely that any pro team would take a chance on him at this point.