Citing multiple unidentified sources who attended an international anti-doping conference in Colorado Springs, Colo., last November, SI.com reported that lead BALCO investigator Jeff Novitzky alleged that Mosley began using those two drugs, as well as EPO, two months before the light middleweight championship fight won by Mosley.

A BALCO client, Mosley was subpoenaed in the Bay Area Laboratory Co-Operative investigation and testified before the grand jury in 2003. He has always denied doping and has never tested positive.

According to SI.com, evidence seized during the BALCO raids showed Mosley had blood work done to measure his hematocrit level, the volume of red blood cells, at 44. In a calendar with his file, the date of July 26 was circled, accompanied by the word "start" and the letter "e," the Web site reported, and the boxer's level increased to 52.2 by Aug. 8.

"Most men are in the low 40s," Dr. Gary Wadler, a member of the World Anti-Doping Association, told SI.com. "Anything over 50 is considered off the charts."

According to that same calendar, Mosley received a final dose of EPO, which stimulates red blood cell production, on Sept. 8, five days before the fight, SI.com reported.

Blood doping has long been an issue in cycling and running, where athletes have boosted red blood cells to increase the capacity to carry oxygen to the muscles.