Last year, long before the Essendon scandal had surfaced, officials from a rival club met a man with the means and knowledge to organise for them to receive a range of performance-enhancing substances for their players.

In effect, the surprised officials were given a sales pitch on how to improve their players' physical performance. As they were told, there was little limit to what they could obtain for their players without fear of detection: human growth hormone (HGH), testosterone, various peptides and substances that were sourced from animals and a range of stuff that most chemists wouldn't know.

This spruiker also had significant knowledge of what Essendon was doing, that much was made clear to them, but he also dangled far greater opportunities. All manner of substances - banned and legitimate and some barely known, including those sourced from animals - were offered.

What did they want? He could get them anything. He could get them selective androgen receptor molecules (SARMs), which boosted testosterone levels. He could find cognitive substances that would improve the players' decision-making. One of these, Cerebrolysin, the pig's brain peptide, is thought to have been given to Essendon players.

Or they could have old-fashioned HGH, which Essendon was believed to have spurned.

In effect, the expert told and sold the officials on the possibilities - and there were a hell of a lot of them. Much of what was being offered couldn't be detected via drug testing. Other substances were not banned; still others weren't even on the radar of the World Anti-Doping Agency.

It was possible, the expert said, for the players to have specific amino acids tailored for their body.

The officials didn't walk down the doping road, but the path was and remains open to those who wish to walk it.

The question of how many footballers are cheating, or doping, as they put it in that athletic nether world, is difficult to ascertain.

Player sources have suggested that it could be 20 to 30 players, from various clubs, using a range of measures such as transdermal creams for testosterone and supplements that boost HGH production.

Some believe the number is far higher; others are dubious there are more than a handful. But this depends also, to a degree, on the definition of doping, since there are grey zones and today's legitimate practices are tomorrow's no-nos.

Players routinely use caffeine to get a pre-game pick-up and arginine, a natural amino acid that boosts growth hormone levels.

Players have gone to the AFL and expressed their concerns about what might be happening. To this point, with the exception of Essendon, there has been no solid evidence, besides the suspicion that small clusters of players are using substances that aren't kosher.

But two factors are clear from the Essendon situation. One is that the AFL can no longer take any pride in the empirical fact that no AFL footballer since 1997 has recorded a positive test for WADA-banned substances (Richmond's Justin Charles being the last one).

Indeed, one could argue that, far from being a fact to celebrate, the failure to detect any doping for more than 15 years actually represents some kind of failure.

Consider the stakes for footballers who have bung knees and ankles and mightn't get that critical contract extension. Or those who aren't strong enough to make it, or those who need a stronger body to withstand injury and fatigue.

Football fans, to a degree, have had the luxury of watching the game from inside a bubble of innocence, believing the AFL - despite its commercial success and cutting-edge practices in everything including sports science - is immune from the cheating that plagues lesser sports.

Not now.