A delayed diagnosis means Marcus Bontempelli remains eligible for the Brownlow Medal despite putting an opponent on the sidelines for up to a month.
Bontempelli was fined $2000 for rough conduct after his late bump on Nick Haynes temporarily forced the GWS defender from the field.
AFL match review officer Michael Christian assessed the Western Bulldogs star's conduct as careless and low impact.
But it emerged on Tuesday that Haynes had sustained a fracture to the cricoid cartilage in his throat and will miss two to four weeks.
That would put the Giants backman out of action for their week-one elimination final, and potentially longer should they win that match.
It's understood Haynes was still being assessed when Christian delivered his findings on Monday afternoon, limiting the information available to him.
An upgrade to high or severe contact would have left Bontempelli facing a multiple-week suspension or referral to the tribunal.
The Giants are believed to have been disappointed with the process, although Christian is limited to assessing the evidence available at the time.
It means while Haynes is sidelined, Bontempelli remains a leading contender to win the Brownlow Medal and is free to play for the Bulldogs in their massive round-23 match against Adelaide and in the finals, should they qualify.
Haynes played out the game but was still struggling to breathe afterwards.
"It's a very rare one," Giants football boss Wayne Campbell said on Tuesday.
"Our doctors haven't seen one before and he managed to see out the game, but couldn't breathe at the end of the game.
"The doctors did the right thing by him after that and disappointingly (he) will miss this week."
Bontempelli has never been suspended in his 125-game career.
The 23-year-old has been installed by bookmakers as third-favourite to win the Brownlow, trailing Geelong's Patrick Dangerfield and Fremantle's Nat Fyfe.
Australian Associated Press