Washington Wizards' Jason Collins (L) goes to the basket against Chicago Bulls' Taj Gibson during the first half of their NBA basketball game in Chicago, Illinois, in this April 17, 2013 file photo. [Photo/Agencies]

NEW YORK - Jason Collins decision to come out as an openly gay male athlete will serve as a test case for U.S. sports leagues, his future teammates and fans.

Not to mention Madison Avenue.

Collins, a veteran center in the National Basketball Association (NBA), on Monday became the first male athlete active in a major U.S. team sport to reveal himself as gay, a moment that could be a watershed for advertisers.

Backing an openly gay male athlete with an endorsement deal is not without risk for corporate marketers who are due to spend an estimated $20 billion this year on sports sponsorships, pitching shoes, beer and cars to consumers who have varying views on gay rights.

Nike, for one, was quick to offer support. "We admire Jason's courage and are proud that he is a Nike athlete. Nike believes in a level playing field where an athlete's sexual orientation is not a consideration," the sports apparel and shoe company said in a statement.

A Nike spokesman said the company does not discuss the details of its contracts with athletes.    

Other companies could also be supportive, given the huge marketing opportunity presented by a gay, lesbian, transgender and bisexual community that contributes $790 billion annually in spending to the U.S. economy, according to Bo Witeck, a gay-marketing strategist and corporate consultant.

As the first openly gay NBA player, Collins, 34, is likely to receive attention from sponsors looking to tap into that demographic, although it remains to be seen where, or if, he will play next season. Collins played last season with the Boston Celtics and then the Washington Wizards and is currently a free agent.

"He's going to witness a lot more endorsement options open to him and he'll be hearing from people in the next stage of his career - insofar as he continues to perform well," Witeck said.

Collins' announcement came on the heels of several high-profile American institutions adopting policies that are more gay and lesbian friendly. Last month, the National Hockey League (NHL) aligned itself with an anti-discrimination group. And last week, the National Football League (NFL) said it would work with the New York Attorney General's Office to ensure that gay players aren't discriminated against.

"The first step is for there not to be any kind of adverse impact on athletes who identify themselves as being gay or lesbian," said Marc Ganis, president of the consulting firm Sportscorp. "It's not so much looking for an advantage but not being viewed as a disadvantage."

Gay athletes, including now-retired pro tennis player Martina Navratilova, have been snubbed by sponsors in the past. Witeck said Navratilova, a lesbian, "didn't get any attention from sponsors because sponsors saw her as a toxic, high-risk deal and thought blowback would be severe."

But recent polls show public opinion is fast moving toward greater acceptance, although a core of social conservatives oppose such change.

For Collins, the chance to land big endorsements may depend on how he plays in coming seasons, rather than his sexual orientation. He is regarded as a journeyman, not one of the NBA's recognizable, bankable stars.

If a star athlete in one of the big four pro men's leagues - the NBA, the NFL, the NHL or Major League Baseball - were to come out, he may be looking at a massive endorsement deal.

"I don't see this exclusively dealing with gay-oriented products. It would be any product that would want a foothold in a broad market and it wouldn't exclude the holy grail of shoes and soft drinks," said Robert Boland, academic chair and professor of sports business at New York University's Tisch Center.

That could happen shortly, said Witeck.

"The ones that'll break out are younger players who were openly gay since they were aware of it. And that'll happen in next five years - maybe even the next two or three," said Witeck.