Carl Nassib ain't the first gay man to play in the NFL -- so says Warren Moon who claims he had "several" gay teammates who just never felt comfortable to come out publicly.
"Really proud of Carl Nassib," Moon tweeted late Monday ... "The first active football player to ever do so."
"I played with several guys who never were comfortable enough to go public. They were great teammates, & obviously very talented."
"As long as they helped us win and were great teammates- their sexual preference was never a issue.