I don't know exactly what the St Kilda players said that so upset Carlton's AFL star, Marc Murphy.

And there's no point dignifying the endless speculation on social media.

What I do know is that Marc Murphy found the comments highly offensive and stated that publicly on Twitter:

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What has also been widely reported, is that whatever exactly the comments were, they certainly had nothing to do with his elite skills as a footballer.

No. They were another tired attempt to sledge, undermine, or mentally disintegrate.

Perhaps that's what Murphy did in return to St Kilda's Jake Carlisle, as he ran past the injured Saint and said something that prompted an all-in brawl.

Call it what you will, citing a player's personal circumstances — whether true or not — to gain a mental edge is grubby and demeaning.

The AFL Players Association has raised the prospect of a code of conduct governing what it calls "on-field issues".

AFL supremo Gillon McLachlan says players know the line that can't be crossed on sledging. ( AAP: Julian Smith )

Its chief executive, Paul Marsh, said in a statement: "With respect to a potential players' code, we can see both the opportunity and challenges in how it might work and we will discuss its merits with our board and players during mid-season club visits before finalising any position."

The AFL's chief executive, Gillon McLachlan, today said the current laws are enough:

"My view is that we have plenty of rules," he said.

"There is a line out there and I think generally it's not breached."

But later the AFL's general manager football operations, Simon Lethlean, added this qualifier: "There is a line, and that line is crossed when offensive and derogatory language is used about women."

Time for another line to be drawn by AFL

The AFL has led the way in stamping out discrimination, be it racism, sexism, or homophobia on the football field.

It has rightly been applauded for taking a stance that in some areas has helped create a broader change in society with regards to people's human rights.

Human rights at their most basic, are about respecting someone's dignity: their individuality and freedom to live as they choose without the threat of discrimination.

How then is personal abuse different? Sledging is simply an affront to someone's dignity and there should be no place for it in sport.

The abusers will claim they're trying to get a mental edge. Here's a thought: get a mental edge by playing better than your opposition.

We don't accept personal sledging in any form in general life, so why accept it on the sporting field?

Perhaps it's time for the AFL to make another bold move and ban any form of personal abuse during the game.

The adage that what happens on the field stays on the field, has long since had its day — quite frankly, it's bullshit.