Didulica had an illustrious career in both the NSL and Europe for Melbourne Knights, Ajax, Austria Vienna and AZ.

The Olyroo, who went on to play for Croatia at international level, was a North Geelong Warriors product who spent more than a decade playing in Europe.

But it was in 2006 in Holland when a bad concussion changed his life.

And now at the age of 42 he is still suffering from the affects of concussions that he received on the the pitch.

"I feel like I am a different person," Didulica told the FIFAPRO website.

"I have headaches every single day of my life. I struggle with sunlight, the glare is killing me. I wear sunglasses all the time. I react to noises. I get the fog and then I can’t think anymore.

"If it has been a busy day or if there have been a lot of people, then I am in bed by 8 or 9 o clock. I’m tired and drained, and I start slurring my words. I also think my brain is affected. I am not saying I was Einstein, but my results in school were good.

"Now, it is much harder for me to process information. I am still going to university to activate my brain and challenge myself, but it takes me a lot longer to process.

When he was playing Diduclia says he was never aware of the long-term health risks associated with concussion.

"There was no research out there," he said.

"You go down, no problem, you’ll recover. Now I know I am not going to recover. There is no way in the world I am mentally the same as I was in 2006. I could easily become depressed, knowing what I used to do and what I can’t do now.

"I can’t have a normal job now from 9 to 5. I can’t process that, my head would be spinning. I can’t live a normal life. And honestly, I’m afraid of what the future holds. Will I become depressed and want to kill myself?

"I do fear maybe a dementia coming on. I am only 42 years old.”

FIFPRO is campaigning for an improved concussion protocol in professional football that  gives medical staff up to ten minutes to take a player to the changing room to decide if he has a concussion.

A temporary substitute could be used and return to the bench if the player is not diagnosed with a concussion and is fit to return to play.

“It is definitely a good move for the safety of the player," Didulica said.

"They should have done it a long time ago. Now that we have more information about concussion and more expert opinion, this shouldn’t even be debated. You need time to assess a concussion. And you need a quiet environment.

"The last thing you want to do is making a decision in 20, 30 seconds while in front of fans. You have to ask questions, you have to settle the player down and you have to make an educated decision."