Until recently, Emmanuel Rodriguez worked on a stage, under bright lights, amid intense competition and before cheering fans. He was a professional video-game player, and a world champion.

Now he works at the customer service desk of a Sam’s Club in Dallas.

Rodriguez, a brash 23-year-old whose nickname in the gaming community is Master, dominated an international field in July in Dead or Alive 4, a popular fighting game, on the Microsoft Xbox 360. He picked up $5,000 and a trophy for the victory.

The competition, held in Los Angeles, was part of the world individual finals of the Championship Gaming Series, a league started two years earlier by News Corporation and DirecTV. And Rodriguez, given his success and his swagger, was a star. As a designated franchise player, he received a base salary of $30,000. During the regular season, he lost only one match, good enough to be named North American most valuable player.

For Rodriguez and others like him around the world, playing video games had become a career.

That, however, has changed for many players. Video games may be as popular as ever  people in more than 65 percent of American households play, according to the Entertainment Software Association  but the professional sport of gaming has nearly collapsed.