NEW YORK — The head of the players' union said Thursday baseball's drug agreement could be undermined by leaks to the media about whether players are cooperating with an investigation by the commissioner. Alex Rodriguez and Ryan Braun are among the players being interviewed as part of Major League Baseball's inquiry into Biogenesis, a closed Florida anti-aging clinic accused of distributing banned performance-enhancing drugs. "Repeated leaks threaten to harm the integrity" of the drug agreement, union executive director Michael Weiner said in a statement.