CARLTON defender Lachie Plowman's two-match suspension for rough conduct has been upheld following a marathon hearing at the AFL appeals board.

Plowman's two-match ban for a bump that concussed Hawthorn's Jaeger O'Meara was previously upheld at Tuesday's AFL tribunal but the Blues appealed that decision based on the argument that "an error of law" had been made.

The latest hearing found there was "grounds" to criticise AFL tribunal chairman Ross Howie for directing Tuesday's jury not to consider Plowman's attempt to spoil part of a marking contest.

But after deliberating for more than an hour, the appeals board of chair Murray Kellam, Stephen Jurica and Geoff Giudice, said any issues with those directions weren't enough to overturn the tribunal's original decision.

"Whilst there may be legitimate grounds for criticism for part of the jury directions, we considered there's no basis to say any such error justifies the reversal or modification of the tribunal decision," Kellam said.

"We affirm the tribunal decision."

Carlton lawyer Peter O'Farrell had argued Howie had been "erroneous" in directing Tuesday night's jury not to consider a spoil part of a marking contest.

"The jury's consideration of what was reasonable was ill-informed because they weren't allowed to consider what is permitted contact under the laws of our game," O'Farrell said.

Kellam agreed that Howie had been "clearly wrong" in giving that direction.

But the AFL's legal counsel Jeff Gleeson argued even if the tribunal jury had been poorly directed, Plowman had executed a bump, not a spoil, in the contest.

Gleeson said any misdirection wasn't enough to overturn the decision.

Plowman did not attend the hearing.

The defender wouldn't have faced the Swans on Sunday regardless after suffering a corked knee in the Hawthorn game but will now also miss the following week's clash with West Coast.

Carlton football boss Brad Lloyd said the Blues respected the appeals board's decision.

"We will always support our players when their sole intention is to contest the football and their eyes remain on the football in a marking contest, as Lachie did in this case," Lloyd said.

"We thank the AFL Appeals Board for their time and respect their decision.

"The Club will continue its preparations for Sunday’s clash against the Swans and we look forward to the challenge."