Without comment, the justices declined to hear the case involving a segment of the $1.5 billion fantasy sports industry in the United States, in which participants manage imaginary teams based on the real-life performances of professional players.

The lawsuit involves C.B.C. Distribution and Marketing Inc., a Missouri company unable to obtain a license from a subsidiary of Major League Baseball to use players' names in C.B.C.'s fantasy baseball games.

The Missouri company sued, saying it did not need a license to continue to sell its fantasy baseball games on its Web site.

The baseball players' union jumped into the case on the league's side, alleging a state law violation of the players' publicity rights — the ability to profit from the commercial use of a person's name.

A federal court and the 8th U.S. Circuit Court of Appeals in St. Louis ruled in favor of the fantasy baseball business, saying that enforcing state law rights would violate C.B.C.'s right of free speech protected by the First Amendment.

The National Football League Players Association supported professional baseball's request that the Supreme Court hear the case.