Messages left Tuesday with the FBI and Edwards' public defender were not returned. Jan Diltz, a spokeswoman for the U.S. attorney's office, declined to discuss the matter.
"There is nothing in our public documents that identify the person," she said. "Beyond that, there's nothing really we can say."
Belliard previously was identified in the case by the St. Louis Post-Dispatch.
Edwards, of Belleville, Ill., made a brief appearance Monday in U.S. District Court on a new indictment returned five days earlier, which added a wire fraud count to an extortion charge leveled Jan. 22. Prosecutors secretly presented the matter to a federal grand jury, bypassing a possible preliminary hearing during which the athlete might have been publicly identified or required to testify.
Federal Magistrate Judge Mary Ann Medler has ordered Edwards to remain jailed without bond pending trial, saying his criminal past makes him a flight risk and public danger. Edwards has a history of arrests on drug charges in Illinois, California and Georgia, and is on parole in a federal drug-dealing case. He also has various weapons convictions.
Edwards is accused of trying to extort $150,000 from the athlete after claiming his daughter became pregnant after meeting the athlete last fall at a St. Louis nightclub.
According to the new indictment, Edwards told the athlete's agents by telephone that a paternity test proved the athlete had impregnated his daughter, and falsely identified health-care providers he said had tended to his daughter before an eventual miscarriage.
Grand jurors found that Edwards knew the office he named had not provided obstetrics or gynecological care to his daughter, and that he prepared two bogus forms -- including forged signatures from a doctor and office worker -- from a health-care provider in East St. Louis, Ill.
Even after the supposed miscarriage, the indictment alleges, Edwards said he and his daughter still wanted to be paid to keep them from telling the media.
"In doing so, the defendant preyed upon John Doe's fear of economic harm from such publicity," the indictment says.
Kevin Curran, Edwards' public defender, has asked a federal judge to throw out some of the evidence, including four conversations monitored and recorded by the FBI in January between Edwards and the athlete's agents.
Curran also wants excluded as evidence $66,500 in cash, two handguns, notes, letters, photos and ledgers he said in court papers that investigators found in Edwards' home. A hearing on that matter has been scheduled for March 29.
Belliard, 31, last season hit a combined .272 with 30 doubles, 13 homers and 67 RBIs with Cleveland and St. Louis, for whom he started at second base in the World Series. In parts of nine seasons with four Major League clubs, Belliard has hit .272, with 80 homers and 439 RBIs.
Last month, Belliard agreed to a non-guaranteed, Minor League contract with the Nationals that will pay him $750,000 if he makes the team. At the time, Nationals manager Manny Acta said, "I think it's safe to say this guy is on our club."