The players' union says Major League Baseball may be responsible for leaking the name of the drug for which Rafael Palmeiro tested positive and might file a grievance, the New York Daily News reported Saturday. The union will discuss the issue with the commissioner's office Monday, Gene Orza, chief operating officer of the players' association, told the newspaper. MLB spokesman Pat Courtney told the News the commissioner's office was unaware of a possible grievance. MLB has not specified what drug the test found, but The New York Times and The Associated Press, each citing a person with knowledge of the sport's drug-testing program, said it was stanozolol. A call to the union office by the AP on Saturday was not immediately returned. Union spokesman Greg Bouris called the leak a "very disturbing matter," but would not comment further in an e-mail to the AP.