Sports Illustrated magazine is reporting that four sources independently have told the publication that the Texas Rangers shortstop, who won the American League home run title and the most valuable player award, was one of 104 players who tested positive.
"We are disturbed by the allegations" in the Sports Illustrated story, an MLB statement said.
The tests were supposed to be anonymous under the agreement between the commissioner's office and the players association and weren't meant to catch players cheating, but rather determine if the drug problem in baseball was rampant enough to merit further testing.
The list was seized by the federal government as part of the ongoing BALCO investigation into former MLB all-star Barry Bonds, who was indicted in 2007 for allegedly lying under oath about using steroids, and others.
While Rodriguez, who recently has made more headlines for his love life, is staying mum on the story, he did deny, in a 2007 interview with "60 Minutes," having used steroids, human growth hormones or any other type of performance-enhancing substances.
Now, even if he does attain the accomplishment, it may come with an asterisk at the end of his name if some critics get their wish.
The one thing Rodriguez may not have to worry about: though Major League Baseball has prohibited the use of steroids without a valid prescription since 1991, no penalties existed for a positive test until 2003. So the bankable star, who earns $27 million annually, may avoid criminal prosecution.