The documents being held by federal prosecutors in California were meant to be confidential, the newspaper said. A lawyer, speaking on the condition of anonymity, said there are plans to question the players about positive steroid tests in 2003 and how they obtained whatever substance was found in their urine sample.

The Major League Baseball Players Association has notified prosecutors it intends to file a motion to quash the subpoenas, the newspaper said. The union claims the documents were seized illegally.

Anonymous tests from the BALCO steroid distribution case put the sport and its players union under intense public scrutiny about alleged steroid abuse.

A grand jury in San Francisco has indicted former Giants' slugger Barry Bonds for allegedly lying to investigators and MLB has conducted an extensive investigation that concluded there has been widepsread use of eprformance-enhancing drugs by MLB players.