Kane Cornes outlines major flaw in Isaac Heeney's AFL Grand Final excuse as footy great gives his theory on Sydney superstar's pitiful performance

Kane Cornes has refused to believe Isaac Heeney's stress fracture 'excuse' following his woeful performance in the AFL Grand Final.

Heeney, who had been tipped for the Brownlow Medal before his suspension ruled him out of contention, failed to deliver for the Swans as they were trounced by Brisbane in a 60-point demolition at the MCG.

He came off the footy field midway through the final quarter and Sydney coach John Longmire revealed post-match that his star man has been struggling with a stress fracture to his ankle for the finals series.

But Cornes has rubbished that claim and pointed to Heeney's 11-touch performance in their 2022 defeat by Geelong to suggest that the midfielder does not prepare well enough for the big games.

'He was the hottest player in football coming into this game ... he was walking on water in the qualifying final,' Cornes said.

'In the prelim final, Port Adelaide had no answers – he was a man possessed.

'To turn up and not give the performance that he had all year.'

Referring to the stress fracture excuse, Cornes said: 'Yeah, well, there was no stress reaction in his shin in the prelim final or qualifying final, so don't give me an injury excuse,' Cornes continued.

'11 disposal performance in 2022, yesterday he hardly went near it and no influence. I just don't want the injury excuses.

'Isaac has to look at his preparation in the big games, and why he has failed again as the best player in football this year, but not on the biggest stage.'