(Reuters) - San Francisco Giants All-Star outfielder Melky Cabrera has been suspended for 50 games without pay after testing positive for testosterone, Major League Baseball (MLB) said on Wednesday.

The 28-year-old from the Dominican Republic, the most valuable player in this year's All-Star game, was hit with the ban for violating MLB's drug prevention and treatment program.

Cabrera's suspension is effective immediately, the baseball commissioner's office said in a statement.

The eight-year big-league veteran is batting .346 with 11 home runs, 84 runs scored and 60 runs batted in this season.

San Francisco is tied with the Los Angeles Dodgers for first place in the National League West with a 64-53 record. The Giants have only 45 games left in the regular season.

(Reporting by Mark Lamport-Stokes in Los Angeles; Editing by Steve Ginsburg)