UMPIRES must make duty of care to the players a priority when adjudicating on dangerous tackles, says Geelong midfielder Mitch Duncan.

Duncan said with concussion such a serious issue for the game he had no problem with an umpire erring on the side of caution when paying free kicks for such tackles.

What constitutes a dangerous tackle became a talking point after the AFL umpiring department confirmed Essendon's Courtenay Dempsey deserved to be penalised for his tackle on West Coast's Andrew Gaff last Thursday.

Duncan did not comment specifically on the Dempsey incident but backed the umpire’s judgment in such situation.

"The duty of care to the player is first and foremost, and if the umpire in that split second deems it to be dangerous then we have to live with that, because concussion is such a serious thing these days," Duncan said.

Duncan was on the receiving end of one of the fiercest tackles the game has seen when GWS ruckman Shane Mumford wrapped him up in round two. (Watch the incident by clicking on the video player at the top of the page.)

The talented Cat said Mumford's tackle was fair, particularly given the damage the ruckman could have caused if he had chosen to bump.

"He could have done a lot worse, that is for sure," Duncan said.

"He could have elected to bump and really put me into hospital but he did the right thing and it was just accidental head contact with his chest."

Duncan said that players knew the difference between a fair and unfair tackle but accepted that the umpires might sometimes see things differently.

"You definitely know a fair tackle and an unfair tackle," Duncan said.

"Sometimes the umpire can't think what you are thinking at the time, and if he thinks differently then you just have to get on with the game."

Duncan said there had been some confusion in relation to what penalty should be a applied for a 'tummy tap' after Essendon's David Zaharakis became the first player suspended for a punch to the stomach this season.

However he said there was a simple solution to clear up any confusion: don't punch.

"You just don't punch anyone in the stomach. I don't want to be losing $1500 so I won't be doing it and I don't want to miss a week, so they're the risks that you take if you do," he said.