Chris Masten is found guilty by the Tribunal of biting Fremantle's Nick Suban and is handed a two-match suspension.
Masten pleaded not guilty and argued he had reacted instinctively to Suban pressing his forearm into his mouth.
The Eagles even called a dental surgeon and jaw expert to explain the jaw reflex that could have taken place when Masten felt pressure inside his mouth, also using former coach John Worsfold as a character reference.
But evidence from Suban and a damning photograph of the Dockers midfielder's arm meant the jury had little room to move in suspending Masten for biting.
Masten was clearly shattered when the result was handed down and will now miss matches against the Western Bulldogs and Adelaide, returning for the final regular season match against St Kilda.
Asked if he had bitten Suban, Masten said: "Absolutely not … my mouth is wedged on his forearm. There was no intention to bite. I must have closed it by reaction".
A photo of Suban's left forearm was shown to an AFL investigator on Monday and again to the Tribunal on Tuesday, showing a clear breaking of the skin, which Fremantle said had required treatment and a course of antibiotics.
Suban also gave evidence that that backed up his match-day comments to an umpire, telling the Tribunal he felt a bite on his arm.
Masten's case was built on the biting action being an involuntary reaction to pressure in his mouth, with the Eagles calling on dental surgeon Dr Robert Delcanho, who said a "physiological reflex" could have occurred "activating jaw-closing muscles".
Worsfold gave character evidence, saying Masten was "a very fair player" and it was not in his nature to fight or wrestle opponents.
As he left the Tribunal in Perth, Masten said: "I got a really fair hearing, just unhappy with the decision obviously. We'll get on with it in a couple of weeks."