NBA center Jason Collins on Monday announced that he's gay in a story for Sports Illustrated, becoming the first active player in one of the four major American professional team sports to announce that he is gay.

"I didn't set out to be the first openly gay athlete playing in a major American team sport. But since I am, I'm happy to start the conversation," Collins wrote. "I wish I wasn't the kid in the classroom raising his hand and saying, 'I'm different.' If I had my way, someone else would have already done this. Nobody has, which is why I'm raising my hand."

NBA commissioner David Stern commended Collins for his announcement.

"As Adam Silver and I said to Jason, we have known the Collins family since Jason and Jarron joined the NBA in 2001 and they have been exemplary members of the NBA family. 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," Stern said in a statement.

Jason's twin brother, Jarron Collins, played for 10 seasons in the NBA, last with the Portland Trail Blazers in 2010-11.

The NBA Players Association also said in a statement that it supported Collins.

"As Jason wrote, pro basketball is a family, and he has and always will be our brother. The NBPA is dedicated to fighting for the best interests of and uniting all players regardless of race, creed, color, age, national origin, or sexual orientation. Today is another example that we are intent on continuing that work.

"We congratulate Jason for having the courage to 'raise his hand,' as he wrote in his story, and start the conversation."

The reaction of other active players has always been a question when it comes to an athlete in a major sport coming out. Other players don't get any bigger than Kobe Bryant, who tweeted his support Monday.

"Proud of @jasoncollins34," the tweet read. "Don't suffocate who u r because of the ignorance of others #courage #support #mambaarmystandup #BYOU"

While Bryant was accepting of Collins, NFL players Mike Wallace and Alphonso Smith, along with former Knick Larry Johnson, were among athletes to take a dissenting tone on Twitter.

Wallace deleted two tweets about the subject, then later wrote, "never said anything was right or wrong I just said I don't understand!! Deeply sorry for anyone that I offended."

Smith, meanwhile, wrote in a series of tweets that, "it's a shame I have to apologize for my TRUE feelings."

Johnson, the current basketball and business operations representative for the Knicks, tweeted: "I don't Jason Collins personally but he seems like a great guy. Me personally gay men in the locked room would make me uncomfortable."

White House spokesman Jay Carney called Collins courageous and said the White House supports Collins and views his decision as another example of progress and evolution in the U.S. as Americans grow more accepting of gay rights and same-sex marriage. Last year, during his re-election campaign, President Barack Obama announced his support for gay marriage.

Hours after Collins disclosed his sexuality, Obama reached out by phone, expressing his support and telling Collins he was impressed by his courage, the White House said.

Former President Bill Clinton, whose daughter Chelsea attended Stanford with Collins, also applauded Collins' announcement.