Whistle-blower: Jose Canseco
Offender: Mark McGwire, Sammy Sosa and other MLB stars
Offense: In his 2005 book Juiced, Canseco named dozens of players he claimed had used performance-enhancing drugs.
Fallout: Canseco's book seemed to be the catalyst for steroid reform in baseball, with a Congressional hearing and the Bud Selig-commissioned Mitchell Report following suit.
Photo: Justin Sullivan/Getty Images, AP