GWS small forward Toby Bedford will miss the Giants' elimination final against St Kilda after failing to have his one-match rough conduct ban overturned or downgraded at the AFL tribunal.

Bedford was charged for his off-the-ball bump on Carlton defender Zac Fisher in the third quarter of GWS' round-24 win at Docklands.

The contact was graded as careless, medium impact and high contact, drawing a one-match ban, after Fisher required a concussion assessment at three-quarter time, which he passed.

GWS argued the bump was not high or forceful and should not be considered medium impact.

Both of those arguments were rejected by the panel of Jeff Gleeson, Darren Gaspar and Scott Stevens, who agreed with AFL counsel Lisa Hannon's argument the potential to cause a head injury meant the bump should be considered medium impact.

Hannon also said the manner in which Bedford approached the ball was unreasonable in the circumstances as he could have elected to shepherd or block without bumping Fisher as strongly as he did.

Gleeson cited video and still photo evidence of Fisher's head appearing to come into contact with Bedford's body in a whiplash motion, and the forward holding his jaw after the incident.

Bedford, ruled out of his first career AFL final at the MCG on Saturday, did not speak.

The Giants relied heavily on testimony from Fisher, who said the bump was not high.

"It was front shoulder against his shoulder," Fisher said.

"Through the shoulder, it was a good bump — but I definitely could've protected myself a little bit better."