In the four major United States team sports (hockey, football, baseball, and basketball), there has never been an openly homosexual male athlete active on the team.
During Raymond Burr's entire lifetime, he hid the fact that he was homosexual. It was a rather open secret in Hollywood. However, Hollywood is only seen as laregly the epicenter of libewral attitudes outside of Hollywood. In a town where image is everything, there are still many closeted lives. Afterr all, there would not have seemed to have been a generalproblem with Jodie Foster admitting to being homosexual, but still she stopped just short of it recently without even a project to promote.
Southern California itself is still a very conservative region of the country.Even David Ogden Stiers hesistated to come out because he feared that it would affect his voice over work in children's cartoons...in 2009. Keep in mind, this is the world of acting where there is a certain 'perception' of homosexuality that is a little pervasive.
If there is that much fear there, it is only compounded in the area of professional sports. After all, there is at least a perception of compromising situations that may arise.
There are also even more intimate connections that develop in sports teams. Particularly, there is the after showers and such. The myth is that they would be exposing themselves to some one potentially sexually attracted to you might some how lead to sexual attraction. You never know, it might even be mutual.
Obviously, it is a personal decision. The additional attention would be paid to someone's career once they made the announcement. As much as Ellen Degeneres statement made in the 1990s, few remember that her show lasted about a year after that.
Of course, that led to other entertainment like Will and Grace and much of what is seen on television today. The trouble is that a professional athlete's career is statistically short (about three and a half years) and that really needs to be the money to set many of the athletes up for the rest of their lives. Anything that might cut that short is an understandeable risk. In what way the first athlete will do it as well could be a matter of some interest. Would they come out at the end when already established? That would lead to questions of when the first athlete would be going in openly homosexual with the knowledge on the table. Would a team balk at the increased scrutiny in signing such a player? All you would have to do is not pick them in the draft, not trade for them, or not sign them to an additional contract once they are one your team. On the other side of the spectrum, we have already seen that happen for perceived controversial views.
So yes, it is a very real concern. After all, no one would owe you a career as a professional athlete even if you did have the skill and could still perform at a high level. All anyone has to do is not sign you or feel like you are the right 'fit' for their team at this time regardless of physical prowess.
An athlete would have to put a higher priority on making a trailblazing statement than they would potentially on their own career. Then others could benefit from it. The sad truth is that they may be sacrificing years of their career as well as viable endorsements in doing so. They may not, but that fear and perception is there until it happens.
Is Andy Messersmith a household name? No, but he did give baseball and by proxy the rest of the sports world free agency. Every year, free agency is now a strategy by both players and owners. Did Messersmith profit? Not really, he was quickly out of the game after opening doors for so many. Many could handle being the next guy easier than the first guy. So, there it stands. It is easier to be encouraging and supportive rather than actually be willing to stake your career and life on a prospect of acceptance. Especially when there are those occassional reminders it might not happen.