Editor's note: A previous version of this story made it seem like Brett Haber knows an active gay player on the ATP tour. He does not. Our apologies for a badly written sentence.

Professional tennis players Andy Roddick and Mardy Fish this week announced they have joined Athlete Ally to show their support for LGBT athletes. We haven't heard from many ATP Tour athletes on these issues, so this is a great development.

"As an athlete ally, I want to support every athlete to feel comfortable and confident being themselves and to make sure that all people – players and fans alike – are welcome and included in tennis," Roddick said in a statement.

To date, only one male professional tennis player on the ATP has come out publicly that we know of: Paraguay's Francisco Rodriguez. Tennis legend Bill Tilden struggled with his sexual orientation, being arrested for his predilection for young boys. Many successful female tennis players have come out, from Billie Jean King and Martina Navratilova to two-time Grand Slam champion Amelie Mauresmo.

Fish said he looks forward to engaging more in the conversation about homophobia in tennis. One particular area of potential growth is the locker room. Fish said professional tennis locker rooms are "cliquish." He spends most of his time with Roddick and fellow American James Blake. The three of them simply don't use homophobic language.

"Between us, we don't hear that kind of stuff," Fish said. "But for other groups, I'm sure it happens. It's hard to police 150 people in a locker room at a Grand Slam. That's some of what Athlete Ally stands for. I'm still in the locker rooms, so I can voice my opinion. I have strong views on things. Everyone's got good in them. If you can figure out a way to say, 'look man, that's not cool. there might be people in here who are gay and you're hurting their feelings.' There's no right or wrong way to do it, but I'd just approach them."

While Fish said he does not have any gay family members he knows of, he is very good friends with out lesbian Rennae Stubbs, a retired 22-year veteran of the Women's Tennis Association.

Roddick's involvement is due to Tennis Channel sporstcaster Brett Haber, an Athlete Ally ambassador, who recruited the tennis star.

"I just thought of Andy because he's a guy that I know to be really interested in issues of justice," Haber said. "He has a record of standing up for things he believes are righteous causes."

Case in point: In 2009, a tournament in Dubai refused to grant a visa to Israeli female tennis player Shahar Pe'er. In protest, Roddick withdrew from the tournament.

Fish said he doubted homophobic slurs in the locker room was much of a problem because of the kind of men on the tour: "For the most part, tennis players are really good guys. We're really lucky to have guys like Rafael Nadal and Roger Federer at the top of our game."

Haber resounded that sentiment, though he knows the goodness of an athlete isn't always on display.

"The athletes I know are almost universally thoughtful and inclusive," Haber said. "But we also know the group mentality can sometimes be different from the individuals' set of beliefs. I don't know any who have expressed homophobic views to me, but that doesn't mean it doesn't exist, and it doesn't mean that group mentality won't appeal to people's worse side."

Fish said he is not aware of any gay men, either active or retired, in the ATP. Haber said he does know of at least one who is no longer on tour.

Roddick is a former world No. 1 and U.S. Open championship and is now retired. Fish is currently out of the top 100 but has eight career titles and reached No. 14 in 2009. He won an Olympic silver medal in 2004.