WASHINGTON (CBSDC/AP) — NBA center Jason Collins is the first athlete in a major American team sport to announce he’s gay, according to Sports Illustrated, which will run a story on the former Washington Wizards player in its May 6 issue.

“The Gay Athlete: I didn’t set out to be the first openly gay athlete in a major American team sport. But since I am, I’m happy to start the conversation,” the cover reads, which SI tweeted Monday afternoon.

Collins, who has played for six NBA teams over 12 seasons, decided to come out of the closet after the deadly Boston Marathon bombings “reinforced the notion that I shouldn’t wait for the circumstances of my coming out to be perfect.”

“No one wants to live in fear. I’ve always been scared of saying the wrong thing,” Collins wrote. “I don’t sleep well. I never have. But each time I tell another person, I feel stronger and sleep a little more soundly. It takes an enormous amount of energy to guard such a big secret.”

Collins played in a Final Four for Stanford and reached two NBA Finals. His twin brother, Jarron, was also a longtime NBA center. Collins says he told his brother he was gay last summer.

Collins reveals that he didn’t announce he was gay sooner because of loyalty to the teams he played for, saying that his “double life” has kept him from getting close to his teammates.

Reaction to Collins’ decision to come out has been largely positive. He has received support from his former franchise, Kobe Bryant and former first daughter Chelsea Clinton among a wealth of others.

“We are extremely proud of Jason and support his decision to live his life proudly and openly,” Wizards President Ernie Grunfeld said in comments distributed by the team. “He has been a leader on and off the court and an outstanding teammate throughout his NBA career. Those qualities will continue to serve him both as a player and as a positive role model for others of all sexual orientation.”

Bryant, who is sidelined with a torn left Achilles tendon, voiced his support on Twitter Monday morning.

“Proud of @jasoncollins34. Don’t suffocate who (you are) because of the ignorance of others,” he wrote.

Chelsea Clinton tweeted: “Very proud of my friend Jason Collins for having the strength & courage to be the first openly gay player in the NBA.” The two became friends while attending Stanford University.

White House spokesman Jay Carney called the decision courageous and former President Bill Clinton said it was “an important moment for professional sports and in the history of the LGBT community.”

“I hope that everyone, particularly Jason’s colleagues in the NBA, the media and his many fans extend to him their support and the respect he has earned,” Clinton added.

NBA Commissioner David Stern said in a statement: “Jason has been a widely respected player and teammate throughout his career and we are proud he has assumed the leadership mantle on this very important issue.”

Collins says he has no idea how other players will respond to his announcement.

“I hope for the best, but plan for the worst,” Collins said. “The biggest concern seems to be that gay players will behave unprofessionally in the locker room. Believe me, I’ve taken plenty of showers in 12 seasons. My behavior wasn’t an issue before, and it won’t be one now.”

The former 2001 first-round pick is a free agent. He played for the Boston Celtics and the Washington Wizards last season.

“Early in my career I worked hard at acting straight, but as I got more comfortable in my straight mask it required less effort,” Collins said. “In recent days, though, little has separated ‘mask on, mask off.’ Personally, I don’t like to dwell in someone else’s private life, and I hope players and coaches show me the same respect. When I’m with my team I’m all about working hard and winning games. A good teammate supports you no matter what.”

Several male athletes have previously come out after they retired, including the NBA’s John Amaechi, the NFL’s Esera Tuaolo and Major League Baseball’s Billy Bean. But Collins is the first to do so while planning to continue playing.

In February, former U.S. soccer national team player Robbie Rogers said he was gay — and retired at the same time. Rogers is just 25, and others have urged him to resume his career.

“I feel a movement coming,” he tweeted after the Collins news broke.

Female athletes have found more acceptance in coming out; Brittney Griner, one of the best women’s basketball players in the world, caused little ripple when she acknowledged earlier this month she was a lesbian. Tennis great Martina Navratilova tweeted Monday that Collins is “a brave man.”

“1981 was the year for me- 2013 is the year for you,” her post added.

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