Thompson was charged by the Match Review Panel for a high bump on Western Bulldogs defender Brett Goodes during the third quarter of Sunday's clash at AAMI Stadium.
The incident was assessed as level one, drawing 125 demerit points and a one-week suspension, but the 30-year-old's six-year good record reduced the penalty to a reprimand.
Thompson did not risk a one-game ban by challenging, but he will carry 93.75 demerit points and will not be eligible for the Brownlow Medal.
Thompson polled 25 votes to finish equal fourth in the prestigious award last season.
The two-time club champion and 2012 All Australian told the Tribunal his initial intent was to smother what he expected would be a left-foot kick from Goodes.
When the Bulldogs' recruit baulked back onto his right side, Thompson made the "split-second decision" to bump, but said he believed contact was not to the head.
"If I thought I was guilty of that I wouldn't be here tonight," he said. "I feel I've done nothing wrong."
AFL legal counsel Jeff Gleeson SC said vision of Goodes checking his mouth for blood after the incident suggested the contact was high.
A free kick was paid at the time for high contact.
Thompson's advocate Iain Findlay said there was nothing to suggest the midfielder did anything unreasonable in the circumstances.
He said the degree of force was not excessive and Goodes was not vulnerable and could have reasonably expected contact.
However, the jury of Wayne Henwood, Wayne Schimmelbusch and Richard Loveridge concluded Thompson had engaged in rough conduct in circumstances that were unreasonable and the contact was indeed high.
Nathan Schmook is a reporter for AFL Media. Follow him on Twitter: @AFL_Nathan
