Jim Goodwin knows all too well the dangers of concussion in football – and he has got the scar and metal plate to prove it.

That is why the St Mirren manager is fully behind the Scottish Football Association's announcement that they plan to trial emergency substitutes in the Scottish Cup "at the earliest possible opportunity".

Concern over the lasting impact of head injuries may be a major topic in the game today but it was not always taken so seriously.

In fact, Goodwin – never known to shirk out of a tackle during his days as an all-action midfielder – recalled the astonishing tale of how he was able to play on for 33 minutes with a broken skull following a sickening clash of heads as he made his debut for Scunthorpe back in 2005.

The injury was so serious he had to have a titanium plate fitted to patch up his cracked cranium.

Welcoming the announcement from football's lawmakers IFAB that concussion substitutes can take place from next year, the Saints boss said: "I think it's a great idea.

"It's something that other sports have been doing for a long time, such as the NFL and rugby.

"Football is normally slow to catch on. Other sports have been using the likes of VAR long before we caught on but I think it's a step in the right direction.

"The powers that be deserve credit as this is a really important step.

"I've headed the ball far too many times myself and I've had numerous concussions and clashes of heads.

"I remember back to my debut for Scunthorpe a number of years ago now. I fractured my skull in the 12th minute and played on until half-time knowing that there was something seriously wrong with me.

"I didn't want to come off the park and it wasn't until half-time that I started being sick and have blood actually coming from my nose that the doctor and the physio made the decision to bring me off.

"So I think this is a very important decision from the authorities and one I'd certainly welcome.

"I don't blame the medical team at the time as they were very good. It was a clash of heads with Liam Fontaine, who was playing for Bristol City.

"We clashed heads, which happens all the time. I did have big bump but there was no cut, so there was no real obvious fracture there which was identifiable to the physio.

"I did know at half-time that once the blood started coming from the front of my head, through the front of my skull and out of my nose that something serious had happened.

"I went for an X-ray then an operation, so I now have a mental plate at the front of my head.

"I used to laugh about the fact that Petr Cech did his head playing for Chelsea about six weeks after I did mine. He's got a three-inch scar on the side of his head because he's obviously got the money to go private, whereas, when I shave my head, I've got a scar that runs from one side right over the top to the other side."

The rule change approved by IFAB means permanent substitutions can be made if a player suffers a head injury, even if all replacements have already been used.

To avoid potential abuse of the rule, opposition teams will also be able to make a change at the same time.

But Goodwin is more concerned about the bigger picture as he insists the move is necessary to ensure players to do not suffer lasting damage.

"We're never going to take heading out of the game," he said. "I can't see that happening – it's just important that the medical team are given the power to make those big decisions. If we have to bring in independent doctors, then so be it.

"But as a manager I'm happy to make those decisions to protect my players.

"We're now too far on in terms of medical science to be taking any risks with player welfare.

"I know back in the day, it was considered brave to carry on with these things but I don't want to be taking risks with any of my players.

"I can think back to a game when I was Alloa boss. Andy Graham was my centre-half and the big man fell out with me for about a month because I took him off after a head knock. He didn't look right so I dragged him off.

"He wanted to play on but as managers you've got to take responsibility and make those difficult decisions, even if they are key players. It's about protecting their long-term future, not even just the here and now."