Recently in Dallas, more than an hour before game time, Mark Cuban, the owner of the Dallas Mavericks, was in the locker room grinding on the Stairmaster, surrounded by several reporters — their microphones deployed, heads tilted away to avoid flying droplets of sweat.

A reporter for The Dallas Morning News, who writes a blog, asked Mr. Cuban about a bruised Dirk Nowitzki, referring to the star power forward as a “warrior” for his willingness to play while injured.

“We’re not trading him to the Warriors,” said Mr. Cuban. “Bloggers might make that point.”

The comment was a bit of word play, but it illustrates how Mr. Cuban, a prolific blogger himself, feels about some of the bloggers who cover his team.

Last month Mr. Cuban sought to ban bloggers from the Mavericks’ locker room, but the National Basketball Association intervened, ruling that bloggers from credentialed news organizations must be admitted.

Mr. Cuban then decided to let in any blogger — “someone on Blogspot who has been posting for a couple weeks, kids blogging for their middle school Web site or those that work for big companies.”

Tension over sports blogging is one of the strains between sports franchises, leagues and reporters to have emerged during the digital age.

The dispute has grown lately between the press and organized sports over issues like how reporters cover teams, who owns the rights to photographs, audio and video that journalists gather at sports events, and whether someone who writes only blogs should be given access to the locker room.

The explosion of new media, especially with regard to advertising income, has made competitors out of two traditional allies — news media and professional sports.

At the heart of the issue, which people on both sides alternately describe as a commercial dispute and a First Amendment fight, is a simple question: Who owns sports coverage?

League officials argue that too much video and audio on a newspaper’s Web site could infringe on rights holders — the broadcasters who pay millions of dollars to carry live games. And the leagues and teams have their own Web sites, carrying news accounts and footage, that are big business. Major League Baseball Advanced Media, baseball’s Internet arm, generates an estimated $400 million a year in revenue and is growing at a 30 percent a year. Investment bankers have estimated that the business is worth $2 billion to $3 billion.