THE TRIBUNAL looks set to hand down the heftiest penalty of the season so far when it sits in judgement of Port Adelaide defender Tom Jonas on Tuesday evening. 

Jonas will almost certainly be sent straight to the Tribunal for his crude late hit on West Coast midfielder Andrew Gaff, which left the midfielder knocked out in Saturday night's match at Adelaide Oval. 

The Power defender's hit will be assessed and graded by the Match Review Panel on Monday, but if it is deemed to have made severe impact it will be sent to the Tribunal.

It would be a shock if the MRP were to give the forearm strike to the back of Gaff's head anything but the highest grading for impact. 

The Panel set a new precedent in round five this season when it decided Gold Coast defender Steven May's high bump on Brisbane Lions ruckman Stefan Martin had made severe impact.

Martin did not suffer any broken bones, passed concussion tests two days after the match and was available to play the next week, but concussion is now treated as seriously as any injury in the AFL. 

It is enough to earn the severe impact grading, which was once reserved for fractured bones.

May received a five-game suspension for the bump, which was graded as careless, high contact and severe impact.

Jonas will also be sent straight to the Tribunal if the MRP grades his hit intentional conduct and high impact.

The other element of the Tribunal guidelines that should ensure Jonas feels the full wrath of the Panel is the risk of serious injury.

Intentional head-high strikes, "such as those with a swinging clenched fist, raised forearm or elbow" were added to the Tribunal guidelines under the "potential to cause serious injury" clause in 2016.

In the unlikely case that the MRP initially decides the impact of Jonas's hit was high and not severe, they should be compelled to upgrade it to severe under this clause.

Jonas has only been suspended once in his 82 games, earning a three-match ban for rough conduct on St Kilda defender Dylan Roberton in 2013.

Given he now has a clean record, he won't have an extra week added to his penalty as May did back in round four.

The severity of his hit on Gaff, however, should ensure a penalty at least equal to May's five matches or, more appropriately, a six-match ban. 

Gaff taken from the field on a stretcher. Picture: AFL Media