It comes at a time of increasing concern about concussion with a number of players retiring because of concussion-related problems, the latest being St Kilda's Koby Stevens in July. Also in July, it was revealed that head injury-related claims lodged by former gridiron players against the NFL were triple what had been predicted. In 2011 the NFL settled a class action brought by 4500 retired players for close to a $US1 billion, alleging it knew of the dangers of repeated hits to the head but concealed it. The class action had been fought largely on the claim that repetitive head injury put players at increased risk of neurodegenerative diseases, not just the early dementia disease known as chronic traumatic encephalopathy (CTE), which can only be diagnosed at post mortem, but also Parkinson's, and motor neurone disease. Concussion issues forced St Kilda's Koby Stevens into retirement this year. Credit:AAP Pearce’s research utilised a technique known as transcranial magnetic stimulation (TMS) to measure brain activity and motor control. He was expected to recruit retired players with a history of concussion, from among 600 who had responded to an online AFLPA survey in 2014. One-third of them reported high levels of anxiety and depression.

However, later the AFL advised Pearce they would be selecting who he would test. “I mean as a scientist that screams selective recruitment’ said Pearce. Pearce expressed his concerns, but says he was told this was “to ensure they get the right people to be tested in terms of what they reported in the survey”. The research quickly ran into more difficulty within days of a story about his "groundbreaking" research on the ABC's 7.30 being aired. An introduction to the segment described it as the first time the AFL had studied the long-term effects of concussion. Reporter Louise Milligan noted how "sceptical" the AFL and its advisers were about CTE. The fact that the AFL was funding this research at all represented a "significant shift in its attitude towards the long-term effects of concussion," she reported.

But at 9.51am the following Monday an email from Professor Paul McCrory - the leading member of the AFL expert concussion group - arrived in Pearce’s inbox. “Did you get approval from Melbourne University to do that story as per our arrangement which was a specific and non-negotiable requirement if you were going to work at the University?” According to Pearce, McCrory told him that he was unhappy because Milligan’s story reported that the only research being done by the AFL into the long-term effects of concussion was Pearce’s. In Pearce’s account, McCrory said this was "misinformation", because he had been doing that research for years. Professor Paul McCrory. By this time, McCrory had a reputation for publicly ridiculing research that found a link between repetitive head injury and neurodegenerative disease, having, for example, in a Melbourne University address in 2016, stated that the problem in the NFL was grossly overblown, also arguing that the dangers of concussion in the NFL were not nearly as serious as some reports had led the public to believe.

McCrory, via the Florey Institute, said he played no role in Pearce’s departure from the university, while the university said approval had not been provided for the ABC to do the story. Pearce was puzzled as to what long-term research McCrory and the Florey Institute were doing. “I don’t really know,” he said. A few months later, Pearce was told much of his research would be farmed out to others, and he would not be privy to the results. It took 18 months for the AFL to provide Pearce with his first retired player to study, and by the end of his contract he had tested just eight retired players out of an expected 20.