Parque, who pitched for the White Sox from 1998-2002 and whose name appeared in the Mitchell Report in 2007, said he never used HGH while he was with Chicago, but rather during his attempt to come back from a shoulder injury he suffered in 2000. Parque underwent surgery in 2001 and never pitched another full season.
His HGH use started, Parque wrote in a letter to the Chicago Sun-Times on Thursday, while with Tampa Bay after the 2002 season. He started just five games for the Devil Rays that season.
"I know that in admitting to this, I am a cheater, a villain and nothing more than a drug user in the eyes of the media and some fans," Parque wrote in the Sun-Times.
Within the letter, Parque also apologized to White Sox general manager Kenny Williams. Parque said he lashed out at Williams after he was left off the roster in 2002.
Williams had not yet read Parque's confession when the GM spoke with the media late Thursday morning, but he was impressed with Parque's candor.
"At a time when he doesn't have to say it and doesn't have to expose himself like that, I think that shows a tremendous amount of courage and character," Williams said. "Whatever he's done in the past, these are things that he and others like him are going to have to live with. Good for him. He probably has washed away a lot of things that have been on his conscience."
Parque's confession prompted an immediate reaction from Guillen, who laughed upon being told the news.
"Now people know, no matter what you take, you have to have some talent," Guillen said. "[If] you don't have talent and you take that thing you're wasting your time. I mean, I don't have anything against the kid. I don't know the kid. I only played a couple games with him.
"I tip my hat to him," Guillen continued. "At least he's got guts to say so, and admit it, and let people know what he did wrong. We need more of that."
Konerko, who was Parque's teammate from 1999-2002, said players who use performance enhancers to try and revive their careers should be viewed in a different light than those who use them to win awards and stake their places in history.
"We're all human beings and you have to take every single case individually," Konerko said. "It doesn't mean he was right. I liked Jim when he was here and I don't like him any less now. Fans are going to form their opinion. I think it takes guts for him to come out and say it."
"There are three reasons to admit to something," Guillen added. "You're going to make money out of it -- I don't think anybody is going to buy his book. To sleep at night. Or to be noticed and be in the public eye. That's the only three reasons you do that. And I think this kid, to me, just did it because he wants to sleep well. And he wanted to show people out there when you do the wrong thing, it still doesn't work."
David Just is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.