Retired AFL umpire Ray Chamberlain has explained what umpires - and in turn, the AFL - are looking for when it comes to contact below the knees.

The AFL world was thrown into a frenzy following Jackson Archer's horror incident with Western Bulldogs' Luke Cleary, which left the latter knocked out during Saturday's contest.

As a result of the incident, Archer was handed a three-game suspension and was subsequently upheld at Tuesday's Tribunal hearing.

What the league is asking of its players is to be able to assess oncoming contests and judge whether they can perform a high duty of care to their opponents.

Based on Archer's velocity and lack of play on the ball (by admission), the Tribunal found the Kangaroos youngster guilty of rough conduct and should have slowed down before reaching Cleary, saying it was "too little, too late".

Chamberlain said the contact below the knees falls under the guise of rough conduct, as is making forceful contact to the front of the player who has their head over the football.

"The question comes down to, are the players' actions reasonable in the circumstances?" Chamberlain said on AFL360.

Cleary's attack on the football was deemed reasonable whilst Archer's wasn't, given he attacked the contest at "high velocity, with the (opposition) player who has their head over the football" should've had a higher duty of care.

Chamberlain goes on to say the three metrics that assist umpires in deciding whether a free kick is to be paid against the player entering the contest and subsequently the ruling by the Match Review Officer (MRO): A bowling ball action or sliding and the speed in which they do and forceful contact to the players' legs.

Chamberlain suggests that Brisbane's Josh Dunkley should have been penalised for coming into contact below the knees of Sydney's Joel Amartey, flagging the umpire had a skewed position.

However, there are circumstances when contact below the knees wouldn't be penalised, such as diving for a mark, smothering the ball or being knocked to the ground involuntarily.