Leeds United have defended their treatment of defender Robin Koch who stayed on the field after a sickening clash of heads in the Whites' defeat to Manchester United.
The club issued a statement on Monday, insisting concussion protocols were followed after the collision with United's Scott McTominay early in the match at Elland Road.
However, Koch sat down 15 minutes after receiving treatment, which involved heavy strapping to his head after he received a deep cut above his eye, and he was substituted at that point.
The incident, in Leeds' 4-2 loss to Manchester United, has provoked a sharp reaction for the Professional Footballers' Association, which claimed the event demonstrated that concussion rules in elite football are failing players.
Football Association guidelines state that any player who sustains a suspected concussion should immediately be removed from the pitch, and extra permanent substitutions are allowed in such cases. But the PFA believes temporary substitutions to allow players to be fully evaluated before a decision is made about them returning to play are needed.
Leeds have also voiced their support for temporary substitutions.
'Leeds United can confirm that following a clash of heads, Robin Koch passed all of the on-field concussion screening tests that are currently part of the Premier League protocols,' the club said in a statement.
'The player was told if he developed any symptoms he should sit down on the field of play and would be substituted immediately, which is what Robin did in the 29th minute of the game.
'The medical staff at Leeds United have always been in favour of temporary substitutions for head injuries, as it would allow the staff more time to assess an injury and allow a period for symptoms to potentially develop.'
Leeds said the German centre-back will now follow the concussion protocols before returning to play.
The argument in favour of temporary concussion substitutes is to give medical teams time to assess a player more thoroughly in a calm, off-field environment, while the game can continue with no numerical advantage to the opposition.
Temporary substitutes are commonly used in rugby.
In a statement also released on Monday, the PFA said: 'The injury to Leeds United's Robin Koch demonstrates again that the current concussion protocols within football are failing to prioritise player safety,' it said. 'The 'if in doubt, sit them out' protocol is not being applied consistently within the pressurised environment of elite competitive football.
'We see frequent incidents of players returning to play with a potential brain injury, only to be removed shortly afterwards once symptoms visibly worsen. As the representative voice of players in England, we have been clear to The IFAB [International Football Association Board, the law-making body] that we want to see the introduction of temporary concussion substitutes.'
Following the match, Leeds United manager, Marcelo Bielsa, said Koch's substitution was due to the cut, rather than the force of the blow to the player's head.
'He had a cut in his head and what excludes him or made him come off is the cut,' the Leeds manager said.
Chris Sutton, whose father, Mike, a former professional footballer, died with dementia in 2020, wrote on Twitter: 'Football doesn't care about its players. What needs to happen before the concussion procedure changes?'