Thymosin Beta 4, the substance in question. But because TB4 is an "endogenous" substance - meaning it occurs naturally within the body – it has what WADA says is a brief window for detection, and the global drugs body was not optimistic of finding elevated levels of TB4 before it found what is says are abnormally high levels in two players. Essendon said WADA had supplied 'no supporting documents' and that there were 'real doubts' about the significance of its claims. "Nothing that has come from the submission has altered my view or confidence in the players' position," said chief executive Xavier Campbell. "It is clear that WADA does not know what the results mean. There were no supporting documents or evidence in the WADA brief and there are real doubts as to the significance of these claims."

WADA is certain to argue that the test results for the two players verifies that TB4 was also given to the remaining 32, but the defence can run the opposite argument, while disputing the significance of the TB4 readings for the two players. As an naturally occurring substance, TB4 is present in the blood, but experts say that urine testing is often a more accurate measure of what has been in someone's system over a short time frame. That TB4 is endogenous also represents the obvious avenue for the players disputing WADA's suggestion that the "abnormally" high amount suggests it had been administered. WADA decided to send the urine samples to Cologne and re-tested following the AFL tribunal hearing, which found decisively against ASADA - the national anti-doping body - in the judgment that cleared the 34 players. The samples were understood to have been collected through normal testing of AFL clubs and players in 2011-12. ASADA did not have the samples analysed for the presence of TB4 at Cologne, for reasons that are unclear. Sources said WADA, in its brief, offered no explanation in the brief for ASADA's failure to have this testing information. Sources with a knowledge of the case said ASADA would come under attack in the upcoming hearing for a failure to present, or locate, such evidence in the first hearing.