Floyd Landis has sacked his business manager after he threatened to expose the fact that Greg LeMond had been a victim of child abuse.
Landis has yet to speak at the hearing in California
LeMond made the revelation on the fourth day of a hearing into Landis's positive test for testosterone after winning last year's Tour de France.
Will Geoghan implied he would reveal LeMond had been sexually abused as a child if he testified.
After the hearing, Landis's lawyer announced Geoghegan had been sacked.
I was absolutely shaken and shocked
LeMond, a three-time Tour de France winner, said he received the anonymous phone call the night before he was due to testify at the US Anti-Doping Agency hearing.
The 45-year-old said he then traced the call back to Geoghegan.
"I thought this was intimidation to keep me from coming here," LeMond said.
"I was shocked, absolutely shaken and shocked. It was a real threat, it was real creepy."
Geoghegan subsequently apologised for his actions, claiming he had acted "impulsively, after a beer or two".
In a statement, he added: "I apologise to Greg LeMond and his family for the distress I caused by my call.
"I also apologise to the arbitration panel and to Floyd Landis and his legal team for the distraction.
"I have been very angry about how unfair this whole proceeding is to Floyd, a great friend and a greater champion, and stupidly tried to take out my anger on Greg.
"I never thought about keeping Greg from testifying. If I had, I would have concluded that since Greg is such a fierce competitor, my stunt would likely make him more resolved to testify.
"What I did was wrong and very unfair to Greg. I am very sorry about and embarrassed by my conduct."
Meanwhile, five-time Tour de France winner Eddy Merckx has refused to testify at the hearing.
Landis won last year's Tour de France but faces a two-year ban if found guilty of doping at the hearing in California.
"I do not want to be mixed up in this. I have nothing to say and will not testify," said Merckx.
"I know nothing about this business and I therefore don't see in what way I can help clarify things."
Merckx's son Axel is a former team-mate of Landis while the 61-year-old was also an advisor to their Phonak Team.
Landis tested positive for high levels of testosterone after he won the 17th stage of last year's Tour.
The 31-year-old, who has consistently denied using performance-enhancing drugs, could also become the first Tour winner to be stripped of his title.
The USADA hearing concludes on 23 May.