The Caracas paper reports sources close to Edwin Zerpa, president of the federation of amateur baseball in Venezuela -- La Federacion Venezolana -- confirm the findings and investigation. White Sox vice president of communications Scott Reifert said, "We have not been informed of any issues concerning any of our players."
Reifert added Major League Baseball has not been contacted regarding the issue.
I was actually going to pose the question of whether he was using "greenies" in the past, and that MLB's new policy has led to him being unable to get "up" for his outings.
Update [2006-5-1 0:3:8 by The Cheat]: I searched for the Venezuelan report -- I'm a sucker for fun with Google translation -- but it appears that the Lider site is under construction, or at the very least undergoing some site maintenance.