Baseball's drug policy prohibited the use of steroids without a valid prescription since 1991, but there were no penalties for a positive test in 2003.
As part of an agreement with the players union, the testing in 2003 was conducted to determine whether it was necessary to impose mandatory random drug testing across the major leagues in 2004.
The results of the testing of 1,198 players were meant to be anonymous under the agreement between the commissioner's office and the union. SI reported that Rodriguez's testing information was found after federal agents, with search warrants, seized the 2003 results from Comprehensive Drug Testing Inc., in Long Beach, Calif.
