LONDON • A sickening clash of heads between Wolverhampton Wanderers' Raul Jimenez and Arsenal defender David Luiz which left the Mexican striker with a fractured skull has prompted calls for football clubs to be able to make "concussion substitutions".

Jimenez was knocked unconscious after an accidental collision with Brazilian Luiz, who rather surprisingly played on for another 40 minutes until half-time with blood seeping through a head bandage.

Jimenez, 29, needed oxygen on the pitch and was taken to hospital for scans, eventually undergoing surgery for the skull fracture.

"Thanks for your support messages," he tweeted from his hospital bed yesterday. "I will be under observation, and I hope to return to the pitch soon."

Arsenal insisted that they followed Football Association (FA) protocols for head injuries in allowing the 33-year-old Brazilian to play on, with manager Mikel Arteta saying: "I just had news from David that the doc made all the tests and followed all the protocols to make sure that he was fine.

"He responded really well to all of them, but it was a nasty cut. David wanted to continue and he continued, but at half-time we decided to take him out because he was uncomfortable heading the ball."

However, the situation raised questions about whether enough was being done to safeguard players' welfare.

The International Football Association Board, which is the sport's lawmaker, has opened the door for concussion substitutes to be used on a trial basis with the FA hoping to do so in this season's FA Cup. The FA is considering fast-tracking the trial to as early as this month.

Liverpool boss Jurgen Klopp says he would support such a move.

"I know we have concussion protocols and I'm pretty sure Arsenal did that. I'm not sure any rule would help in that moment because the player can play on," he said on Monday when asked about concussion substitutes.

"But, yes, it makes sense that we can do things like this."

Manchester City boss Pep Guardiola called for clearer guidelines on whether any head knock should result in a player being substituted, even if they pass the on-field concussion check by club doctors.

"I don't know the protocols," said the Spaniard.

"Some of them say you have to be immediately out, some of them say no. It should be clear because in the head, it's always so dangerous."

NOT ACCEPTABLE

Former England captain Alan Shearer, who recently hosted a documentary about possible links between a career heading a football and dementia, said a change was long overdue.

"Football needs to get real, it needs to wake up, it needs to get serious. Not next year, next month, now. It's not acceptable, it has been going too far too long," he told the BBC.

"They're on about trialling concussion substitutes. What is there to trial? It's been going on for years. It's not acceptable."

City goalkeeper Ederson, who suffered a head injury and needed eight stitches after being caught by the boot of Liverpool's Sadio Mane in 2017, said such situations required special attention.

"When there is a blow to the head, there should be a substitution - whether the player can continue or not," he added.

Liverpool defender Andy Robertson said concussion substitutes would get the backing of players.

"Concussion subs would make sense. It's not a natural injury getting concussion like that," said Robertson, who was in the Hull side when his then teammate Ryan Mason suffered a fractured skull against Chelsea in 2017 that forced him to retire from football.

"For me and the players, that would make sense. Hopefully that's maybe something that can come in."

FA rules state that if there is any suspicion of a player having suffered a concussion, the player must be removed from the field of play, and not allowed to return.

Brain injury association Headway said Luiz should not have been allowed to play on.

"You simply cannot take a risk with head injuries. They are not like muscle injuries where you can put a player back on 'to see if they can run it off'," deputy chief executive Luke Griggs said.

"One further blow to the head when concussed could have serious consequences."

REUTERS, AGENCE FRANCE-PRESSE