Concussion in contact sports is a controversial, sensitive and topical issue -- and it's also an extremely important one.

It's a very difficult issue for everyone involved -- players, their families, doctors and coaching staff. It's not as simple as other injuries; when you hurt your hamstring, you get a scan, assess it and can determine the damage. But with head knocks and concussion it is much more difficult to assess; doctors make their decisions based on various testing methods, patients' symptoms, vision of the incident and their own experience and knowledge of the individual concerned.

Concussions are an extremely important issue among all key stakeholders in the game. The AFL, AFL Players' Association and the players rely heavily on the advice of experts when determining any course of action on this issue and my situation on Saturday was a case in point.

From the moment I received a knock to the head against Collingwood at the MCG I entered what is known as concussion protocol.

An injured Nick Riewoldt walks off the ground after St Kilda's win against Collingwood. Michael Dodge/Getty Images

Once a player enters the concussion protocol, team doctors have the first, last and only say with respects to the player's ability to return to the field.

When I first retreated to the bowels of the Members Stand with our club doctor, we began to work through an assessment tool known as SCAT3 which is used in conjunction with several other pieces of information to diagnose the possible existence and/or severity of a concussion. This particular test takes into account symptoms and also tests the cognitive function of someone's brain.

We began by answering several orientation questions known as the Maddocks Score. These are questions that anyone not experiencing a concussive episode would be able to answer. Where are we? Who did we play last week? Who kicked the last goal? Which half are we in?

Next, I was given a brief survey to answer based on how I was feeling at the time. Was I experiencing any dizziness? Pressure in the head? Fogginess? Feeling slowed down? Neck pain? And so on.

Next, as a memory assessment, I was given five words to remember: candle, paper, sugar, sandwich and wagon.

Given my natural urge to get back out on the field, coupled with still being able to hear the roar of the crowd, this was a frustrating process to go through. However, I'm fully aware of its necessity and importance.

Next I was asked to say the months of the year in reverse order. Following that I was given a list of numbers and asked to repeat them in reverse order. 163 would be 361. 9845 ... 61742 ... 380475 ...

Following this, the doctor checked my balance. I had to stand on my non-dominant leg, close my eyes and balance for 20 seconds. This is hard for me to do normally, let alone if I happened to be concussed. That's why the test is compared to a baseline of your own results.

It's all about collecting as much information as possible so doctors can make an informed decision.

Can you remember the five words I had to memorise? Just for the record I nailed them and generally performed very well on all of the aforementioned tests and questions. However, there was an element of the vision of the incident that our doctors weren't comfortable with that led them to rule me out for the remainder of the match.

The decision to rule me out of the game certainly wasn't made without an argument from me! I was extremely determined to get back on the ground, but in that situation the doctors are compelled to err on the side of caution and make sure they look after their players' welfare and best interests. I thought I was fine to return, but obviously I wasn't. Still, I felt OK. In fact, on Saturday night, I read a book and started this article -- you can't do that if you're struggling badly with concussion.

On Sunday I went into the club, met with the doctors and performed the same tests again to make sure there was no delayed symptoms. I performed really strongly again, but I still need to tick a few boxes before I'm cleared to play against Hawthorn in my home state of Tasmania this weekend. The doctors will test me again during the week, and I'll have an hour or two of testing with our neuropsychologist. In addition, I'll have to be able to train or perform some sort of physical activity without getting a headache or related symptoms -- basically I'll have to be feeling 'normal', but early indications look promising.

With any potential brain injury you have to be completely honest with how you're feeling. As a whole, players are far more aware of the seriousness of the issue now and it's paramount that we are transparent and honest in relaying our symptoms. It's imperative to trust the experts and listen to what they have to say and heed their advice.

Every head knock is concerning; Saturday's incident was at the minor end of the scale, especially compared to what happened against Adelaide last year. I was unconscious and stretchered off after that collision with Brodie Smith, and I had to be put in hospital overnight.

Nick Riewoldt is assessed by doctors after his head clash during the Saints-Crows game in 2015. David Mariuz/Getty Images

I know scenes like that are very, very distressing for family members; they are so concerned about your health, and I know how bad it looks on TV when someone you care for is in that state.

After that injury against the Crows last year, a lot of people said I should give the game away. Clearly if the advice came back from experts that I should retire then that's what I would've done. But after detailed brain scans and analysis the advice I received was that I had fully recovered and I was at no greater risk than I was prior to the injury. That's really important to know. I wasn't just 'OK' to play again, I was actually at no greater risk than I had been previously.

St Kilda's Nick Riewoldt is taken from the field after his sickening concussion against Adelaide in 2015. David Mariuz/Getty Images

I've got a wife, a young child and a family; In no way would I take any unnecessary risks to jeopardise my future or theirs. If at any stage in the future I am advised it was time to give the game away due to a greater risk of permanent damage, then it'd be an easy decision.

Understanding the science and medicine behind concussion is so important, which is why we put so much trust in our doctors. It gets very frustrating when people grandstand and comment on this issue without any medical background or knowledge.

Of course with any contact sport, there's an inherent risk of injury. However, given there's so much work being done behind the scenes by the AFL and medical specialists, I'm comfortable that the game itself is only getting safer to play.

So, looking a long way down the track, would I be happy for my son to play a contact sport if he wanted to? Absolutely. It'll obviously be up to him, but I think the amount of time and energy going into concussion is only going to make sports safer in the future.

However, in saying that, if James could make it in any sport in the world, maybe golf would be the best option; there's fewer risks, he'd be able to travel the world and play until he's 60 ... not to mention the prize money on offer.