You don't know too much about football players then. Actually, I do. High-school and College ball with invites to Pro combines. Lots of friends who coach and have helped coach. But remember, these are 17 and 18 year olds.
Drug tests are very easy to beat especially if it is a ratio of testosterone to epitestosterone.
In the same years they conducted tests on the same athletes but, guaranteed no sanctions against the athletes for their results. Granted this is a different scale but, the IOC supposedly has the most advanced testing and when the athletes wanted to beat the test, most did. I was stationed in San Diego and have been to Tijuana. You could buy whatever you want for dirt prices. Please don't consider this an affront, I'm just curious how you concluded that.