Troy Ellerman agreed to be sent to prison for as long as two years and fined up to $250,000 for the convictions.
U.S. District Judge Jeffrey White isn't bound by the plea agreement and said he hasn't decided whether to accept it. White said he could impose as much as a 15-year prison term at Ellerman's sentencing, set for June 14.
"The charges cut to the very core of our criminal justice system," the judge said. "This represents a corruption of our system by a member of the bar and by an officer of the court."
The 44-year-old Ellerman, from Woodland Park, Colo., also is likely to lose his license to practice law. He declined comment Thursday.
At varying times, he represented two defendants in the Bay Area Laboratory Co-Operative steroid lab investigation and was privy to sensitive grand jury testimony that he leaked to the San Francisco Chronicle.
After the guilty plea, federal prosecutors announced they dropped their case against reporters Mark Fainaru-Wada and Lance Williams, who were facing prison sentences of up to 18 months for refusing to divulge their source.
"It's great not to have to go to prison _ it's great for our families," Williams said in a brief interview Thursday.
Ellerman admitted he let Fainaru-Wada view transcripts of the grand jury testimony of baseball stars Barry Bonds, Jason Giambi, Gary Sheffield and sprinter Tim Montgomery. Fainaru-Wada and Williams used those notes to write several newspaper stories and a book that reported Giambi and Montgomery admitted to grand jurors that they took steroids, while Bonds and Sheffield testified they didn't knowingly take the drugs.
Prosecutors said a "previously unknown witness" approached the FBI and offered to help prove that Ellerman was the source of the leak. Larry McCormack, former executive director of the Pro Rodeo Hall of Fame and a private investigator who briefly worked for BALCO founder Victor Conte, said he tipped off FBI agents.
McCormack said he shared a Sacramento office with Ellerman and that Fainaru-Wada visited there several times in 2004. McCormack said Ellerman told him about the leaks.
In February 2005, McCormack moved to Colorado Springs, Colo. to work for Ellerman, who then served as commissioner of the Professional Rodeo Cowboys Association.
The association's board of directors fired McCormack in August, but he said Ellerman tried to save his job and his decision to call federal investigators and expose the lawyer had nothing to do with his firing.
"My concerns were whether I could be in any kind of criminal jeopardy," said McCormack, a former Yuba County sheriff's deputy. "Another thing that was bothering me was that the government was spending all of this money on the investigations and these reporters are looking at going to prison _ it ate me alive."
Shortly after McCormack was fired, he said he wore an FBI wire and had a "heated conversation" with Ellerman in which the lawyer made incriminating statements. McCormack declined to discuss the details of that conversation.
Ellerman briefly represented Conte, whose Burlingame-based supplements lab provided performance-enhancing drugs to elite athletes. He later represented BALCO vice president James Valente, and that's when he obtained transcripts of the athletes' testimony from federal prosecutors.
Shortly after the first leak in June 2004, Judge Susan Illston ordered an investigation. Ellerman and all lawyers in the case filed statements under penalty of perjury swearing that they weren't the source. Ellerman even made a motion in October 2004 to dismiss the case against Valente because of "repeated government leaks of confidential information to the media."
Prosecutors said Ellerman leaked the trascripts in a misguided attempt to derail his client's prosecution.
"Such gamesmanship undermines the integrity of the legal system and demands accountability," said Deputy Attorney General Paul McNulty.
Ellerman's lawyer, Scott Tedmon, declined to discuss his client's motives for leaking the transcripts.
"It's difficult for him and his family," Tedmon said outside of court. "He's taking this head-on."
Valente, Conte and three other men pleaded guilty to steroids-related charges in an earlier phase of the investigation.
In addition, chemist Patrick Arnold, Bonds' personal trainer Greg Anderson, and track coach Remi Korchemny all have pleaded guilty in the BALCO probe. Korchemny and Valente were sentenced to probation and the others were each sentenced to jail terms no longer than four months.
The case is United States v. Ellerman, 07-0080.