The Bulldogs challenged Lewis's staging fine, but the tribunal upheld his $1000 fine.
Beveridge said Lewis could not breathe after Sydney opponent Nick Blakey caught him in the midriff as they had a scrap during last Friday night's game.
The Bulldogs coach said the tribunal had disregarded the club's medical report and compared it to soccer.
"If you think of the round-ball game, the World Cup ... what the AFL are saying to us is if you get hit, regardless if you do or don't, if you stay down, you can still be charged with staging ... and fine you," he said on Thursday.
"We submitted a medical appraisal and assessment that he couldn't breathe, he wouldn't stay down otherwise.
"The AFL has obviously thumbed their nose at it and said, 'We just think you've staged'. It must be caught up in the fact he's been on the ground for a while.
"It's a change now to what staging is, it's totally contingent on how long you stay down, not whether or not you actually got hit - because he got hit."
Beveridge added it was "a new precedent in that (tribunal) area".
He felt for Lewis and hoped the incident would not hurt his reputation.
"I don't want him to be tarred with a brush where he's put on an act, because he hasn't," Beveridge said.
"It just means now that if doctors from the football clubs, if they put through submissions that a player is in discomfort, has actually been hit, the AFL will now ignore that and base it on what they see."
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