For the game of baseball, the first openly gay player was Glenn Burke. Burke was an outfielder from 1976-79 with Los Angeles Dodgers and Oakland Athletics. He didn't declare his sexually publicly until after his playing days were over, but was open with his teammates and owners about it. Most weren't bothered by Burke's homosexuality, but some were. Burke wrote in his 1995 autobiography, "Out at Home", that Dodgers GM Al Campanis offered to pay for his honeymoon if Burke would get married to a woman. Burke refused.
Burke later died of AIDS related causes in 1995 and OF Billy Bean(1987-95) is the only other former MLB to announce he is gay. One other sidenote on Glenn Burke, in 1977, after teammate Dusty Baker hit his 30th home run, Burke went out in the field to congratulate Baker and put his hand up. Baker slapped his open hand and the "high five" was believed to be invented.
Hopefully with the announcement of Collins, no player should be worried about being mistreated or judged anymore because of his/her sexuality and go through what Glenn Burke did. A person should only be judged how he/she performs in the workplace including the athletic fields and not by the color of skin, age or sex of a person or the lifestyle they lead. I know we are not there yet as a society, but I think we are moving in the right direction.