I don’t think so (and hope he didn’t). Testosterone (or a misbalanced ratio) would not improve athletic performance over a single day.
Here is a good site with a similar viewpoint to what I have:
We all have every reason to believe that the American cyclist Floyd Landis cheated to win this year’s Tour de France. Not only have his tests come up positive for high testosterone ratios, but damning evidence of exogenous, or synthetic, testosterone has been found as well.
Yet I believe that Floyd Landis is innocent and that we are witnessing a terrible injustice. I’ve lived this sport for 35 years and know the European professional cycling circuit intimately, and I feel strongly that in this case something is wrong.
Whenever an athlete tests positive for banned drugs, you look to see who is close to them. Landis’s trainer, Dr. Allen Lim, an exercise physiologist from Colorado, is an expert in the use of power meters, devices that attach to racing bicycles and measure power output. According to Lim, the “improbable” stage 17 victory on July 20 was a triumph of strategy, science and Landis’s vitality. Landis averaged 280 watts over the five hours of the ride, but he has averaged 320 for six hours in training – documented proof, according to Lim, that the performance was well within Landis’s capability.
(go to the main site to continue reading)
Also, here is a site with more information about the biochemistry of Floyd’s cortisone treatments:
Floyd Landis: Could His Cortisone Treatments Exonerate Him?