TMZ Sports just spoke with a bisexual NFL player who's upset with Michael Sam -- telling us he was OFFENDED when Sam said other gay men in the league are less courageous because they don't want to come out.
The player -- who didn't want to be identified by name -- has played in the league for several seasons and says he's open about his sexuality with close friends.
But when the player read Sam's recent comments about gay men in the league -- he was offended.
Specifically, the player was upset when Sam said ... "I respect the players that did reach out to me and had the courage to tell me that they were also gay, but they do not have the same courage as I do to come out before I even played a down in the NFL."
The player's response -- "As a bisexual man, I just feel like Michael Sam does not speak for all gay men."
"He has his own opinion ... but DON'T say that we don't have the courage to come out. It's totally wrong. Just speak for yourself. No one else."
"It's no one's business what my sexuality is. You should like me for me ... not for who I choose to be with."
The player continued ... "I feel the NFL isn't ready for people to be open about it. Or the General Managers for that matter."
Despite those opinions, the player says he believes Sam DID get a fair shot to make a team -- "I just don't think he performed well."