The Premier League has voted to introduce permanent concussion substitutes.
Teams will be able to permanently substitute players who are diagnosed with, or suspected of sustaining, a concussion during a match once the trial is confirmed. There is no set date for implementation, at this stage.
Both sides in each game will have two such replacements available, as well as their three regular substitutions.
A Premier League statement read: "Premier League shareholders today formally agreed to introduce the International Football Association Board's (IFAB) additional permanent concussion substitutions trial.
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"The trial will be confirmed when the implementation of the reporting processes, including private medical information, has been resolved with IFAB and FIFA.
"The trial is a result of the IFAB's consultation with stakeholders and recommendations from their concussion expert group to allow additional substitutions for players with actual or suspected concussion."
The Premier League is the first competition to agree to the trial. The Football Association is keen to follow suit, having already stated its desire to have the rule in place for the FA Cup fifth round, scheduled for next month.
IFAB, which governs the laws of the game, gave competitions the opportunity to introduce permanent concussion substitutes after approving them on a trial basis in December.
The decision came at the end of a year in which the deaths of England's 1966 World Cup winners Jack Charlton and Nobby Stiles following dementia diagnoses - as well as the diagnosis of Sir Bobby Charlton - shone a light on the impact of head injuries sustained in football.
By Rob Dorsett, Sky Sports News reporter...
For Sir Geoff Hurst, the end of 2020 couldn't come soon enough. Since the summer, he's seen the death of two of his team-mates from the England team of 1966 and heard about the terminal diagnosis of a third.
"It's absolutely unbelievable that the people you've grown up with, team-mates... and then this happens. You learn what they, and their families have been through. It's awful," he tells Sky Sports News.
Dementia has devastated the Boys of '66.
In total, five members of England's World Cup-winning team have developed dementia. It's led to the death of four of them.
Ray Wilson was the first to succumb, in July 2018, with Martin Peters also dying of dementia, just over a year ago.
Jack Charlton died of the debilitating illness in July 2020, Nobby Stiles in October. A month later it emerged that Sir Bobby Charlton is also suffering from the same condition.
"I think we knew they weren't well, but it's always a huge shock when you hear they've passed," says Sir Geoff. "We knew Nobby had been in a home for some time, and we knew Jack hadn't been out and about.
"It's just been a nightmare year. The pandemic has meant you aren't out and about talking to people about your emotions as you usually would. In fact, this is the only time I can talk about it, and I'm getting a bit emotional now with you, because it's the first time I've really got to talk about my team-mates."
Former Tottenham defender Jan Vertonghen revealed last December that he played through concussion symptoms for nine months as he fought to earn a fresh contract.
Vertonghen was injured in Spurs' Champions League semi-final first leg against Ajax in 2019 at the Tottenham Hotspur Stadium after clashing heads with team-mate Toby Alderweireld.
The defender was allowed back into the game after prolonged checks by the Spurs medical team on the sideline, but as he realised his symptoms were too severe to continue, Vertonghen quickly signalled to the bench to be taken off.
"Many people don't know this, but [the head injury against Ajax] affected me for a really long time. I had dizziness and headaches," he told Belgian outlet Sporza. "The other day, there was the story about David Luiz and [Raul] Jimenez, in which Jimenez suffered a fractured skull.
"With me, it was my nose and I continued to play, which I shouldn't have done, according to the doctors. In the end, I think I suffered from that head injury for about eight or nine months. That was the reason why I didn't play well.
"I had a year left on my contract and I thought I had to play because I had to showcase myself to other clubs and to Tottenham, but when I played, I was rubbish. I just couldn't produce a good performance. Not many people knew that.
"That was my own choice and not a criticism of anyone else. After five months, there was a day when I started to feel better. When I see the footage from that time, I know when I didn't feel well by looking at myself."