We all saw it on Saturday.

As the brilliant Billy Slater – knee-high to a grasshopper and weighing not much more – charged towards the Raiders line, his footballing brain instinctively worked out all his options in a split second. Three Raiders in front, three of his own players outside ...

A swerve with verve, a jink to the chink in their armour, a surge, and there is a whiff of a gap, just enough, that if he passes to the man outside him at exactly the right instant, well ...

Well let's see.

The ball is released perfectly, and the Melbourne fullback watches with satisfaction as it hits its mark, right on the chest of his charging teammates.

What he doesn't see – or count on – is Raiders hardman Sia Soliola lining him up from behind, and bringing his swinging arm forward to hit Slater, about a second late, right in the side of the head.

The result was sickening. Internally, that brilliant footballing brain of Slater's smashed into the side of his skull. He went down like a sack of spuds, completely unconscious, and did not move for two minutes. Since, we are told, he cannot remember anything that happened in the previous two weeks.

And Soliola? No send-off! A mere penalty, and get back your 10 metres.

"What do you have to do these days," former Rabbitohs and Sea Eagles hardman Spud Carroll later asked on Fox Sports, "take their head off and put it on a trophy? That was one of the worst I've seen this year. It's the worst we've seen for quite a while. I think the last send-off we saw was two years ago and that bloke should have been straight off."

And so he should have been. In the end, Soliola was given a five-week suspension, with that news breaking at all but exactly the same time as the New York Times released devastating news for the world of NFL football, that also has significant implications in Australia.

For the most influential newspaper in the world revealed that, as published by The Journal of the American Medical Association, a study of the brains of 112 deceased NFL players, showed that no fewer than ... 111 of them showed signs of CTE, Chronic Traumatic Encephalopathy – brain damage to you and I.

No, that is not a misprint. I repeat. When examined by professionals, it was revealed that no less than 99 per cent of NFL players – who receive with varying degrees of intensity much the same brutality as league players – had suffered brain damage.

The implications for rugby league and episodes like the one with Slater are obvious. It is not to say that Slater will end up with brain damage. But it is to say that the more we know about the effects of continued brain trauma, the more obvious it is that this really is serious, and that all of the contact sports, led by rugby league, rugby union and AFL, must act quickly to instantly and severely punish those who play in a manner to unnecessarily put at risk the brain health of their opponents.

And it also means that now, more than ever, football must insist that those who have suffered concussion, must sit it out for several weeks to give their brains a chance to recover.

In response to this column, the critics will carp, as one of the twitterati did to me yesterday: "Fitzy you played a contact sport. You loved it. We all love it. Stop sanitising the world, let us enjoy life and take calculated risks."

Listen, I did love contact sport and believe in calculated risks. But to do those calculations properly, everyone needs to know exactly what it is they are risking, and the more we find out about the effects of repeated concussions, the more obvious it is that it is a lot.

It doesn't mean you shut down football.

It does mean that on every ground – medical, legal, and ethical – the protocols in football not only have to be tight, they have to be observed.

Because there is a hell of a lot more at stake than merely whether a try is or isn't scored, a game is or isn't won, and what position your team finishes on the competition table. We are talking about condemning footballers and their families to decades of dementia, of outbursts of anger, of emotional agony, unless steps are taken right now to minimise the damage. And yes, too, that medical study above says minimising is about the best we can hope for. Deal with it.

Twitter: @Peter_Fitz