The policy was introduced because top baseball officials perceived that some players had too much freedom on testing days.
Commissioner Bud Selig said monitoring was needed because Rob Manfred, baseball's senior vice president for labor relations, and other officials had told him there was "a problem," that some players were not being watched closely enough.
Now, "players may not be aware they're under observation, but we're watching," Manfred said in a recent interview.
Baseball tests the 40-man rosters of all teams once in spring training and at least once more during the season. There also are 600 random tests.
Three general managers, 18 assistant GMs, four vice presidents and four directors of baseball operations are monitors. The title of the other was not disclosed.
"There is absolutely no evidence that a player scheduled for a test is left unattended for a period of time that permits him to defeat the purposes of the test," Gene Orza, the chief operating officer of the players' association, was quoted as saying in an e-mail message. "From the moment the player is designated for a test, he is under observation by the team coordinator."
Gary Wadler of the World Anti-Doping Agency criticized baseball's procedures, which allow players notified of testing earlier in the day up to an hour after that day's game to provide samples.
Pirates. Pittsburgh's Freddy Sanchez, last season's National League batting champion with a .344 average, was placed on the 15-day disabled list and will miss at least four games. He sprained a knee ligament on March 6.
Diamondbacks. Arizona placed pitcher Randy Johnson on the 15-day disabled list. Johnson is returning from back surgery.
Reds. Eric Milton, scheduled to start Cincinnati's final exhibition game, was scratched because of back spasms.
Athletics. Oakland righthander Esteban Loaiza was scratched from his scheduled start with tightness in his right shoulder.
- Inquirer wire services