The AFL appeals board threw out Jack Viney's controversial bumping suspension because he deserved the benefit of the doubt.
The board also found that the Melbourne midfielder's evidence was not tested in cross-examination at the original tribunal hearing.
The AFL has released the detailed findings of the three-man appeals board, a fortnight after the landmark case.
Melbourne appealed after the tribunal found Viney guilty of rough conduct and handed him a two-week ban.
The incident left Adelaide's Tom Lynch with a broken jaw and the match review panel took the unusual case of referring the case directly to the tribunal.
The case and Viney's guilty finding sparked renewed debate about whether the bump was dead in the AFL.
Viney argued he was bracing for contact, rather than trying to bump Lynch.
"Thus there were two equally competing versions of the facts - one which was innocent, and the other which was not," the appeals board wrote. "In that circumstance, there should be a necessary doubt in the tribunal deciding that issue, as there is in an appeal board reviewing the evidence.
"In that situation the alleged offender should have the benefit of that doubt."
The appeals board of chairman Peter O'Callaghan QC, Brian Collis QC and former Richmond premiership player Michael Green found it would be unreasonable for the tribunal or any other tribunal not to afford the benefit of that doubt to the player.
"But there is another important factor justifying the above finding, and that is the evidence of Viney," they added.
"His evidence was that he had no intention of bumping and that he did not do so.
"This was not challenged in cross-examination by the highly competent and experienced [Jeff] Gleeson.
"The board finds that it would be unreasonable for the tribunal or any other tribunal to disregard or fail to take into account Viney's evidence, which resolved the issue of whether it was a bump or a brace in Viney's favour."
The appeals board decided to release the reasons for their findings because of the importance of the case.
They added: "Most importantly, because the board upheld the appeal from a conspicuously competent and experienced tribunal."