Last year's No.1 draft pick, Reid was cited for slinging St Kilda's Darcy Wilson to the ground in the Eagles' 14-point loss at Optus Stadium on Saturday.
Wilson's head hit the turf as a result of the forceful tackle but he was cleared of concussion and returned to the field.
The league's match review officer charged Reid with rough conduct and graded the incident as careless contact, high impact and high contact, drawing a two-match ban.
West Coast argued the tackle should be deemed medium impact, in a bid to downgrade the suspension to one game.
Harley Reid is no longer eligible for the AFL's Rising Star gong following his two-match ban. (Matt Turner/AAP PHOTOS)
Reid, 19, will miss Saturday's game against North Melbourne, then the round-15 game against Essendon after the bye, while he is ineligible for the AFL's Rising Star award due to his suspension.
He did not give evidence on Tuesday night, with counsel David Grace KC speaking as Reid watched on via video conference.
AFL counsel Sally Flynn asserted Reid's rough-conduct charge was a clear example of an inherently dangerous tackle, pointing out the potential to cause a concussion or neck injury.
The tribunal, including chair Renee Enbom KC and panel members Darren Gaspar and Paul Williams, deliberated for 53 minutes and believed there was "considerable" potential for injury from the "poorly executed" tackle.
The AFL's assertion the nature of the tackle - to lift, rotate and sling Wilson backwards onto the ground - had the potential to cause a serious head or neck injury was accepted, maintaining Wilson was "lucky" he landed the way he did.
St Kilda's medical report said Wilson did not require any treatment after the incident.
West Coast cited four examples of previous tackles in Reid's defence.
Will Day's tackle on Brad Close, where the Hawk pinned the Cats' arms and slammed his head into the ground, was shown as an example of high impact.
Jaeger O'Meara's tackle on Charlie Spargo, Charlie Cameron's slinging of Jake Lever and Tom Barrass's tackle on Michael Walters, were all used as examples of medium impact.
Flynn successfully countered all the examples, bar Day, were less dangerous than Reid's slinging tackle, which gave Wilson no opportunity to brace for contact.
Earlier on Tuesday night, Western Bulldogs forward Rhylee West had his rough-conduct charge, and a week's suspension, thrown out.
West successfully argued he had not intended to bump Collingwood's Jeremy Howe, but braced for contact and caught Howe as he went to tackle Maynard.
14°C