Atletico Madrid defender Robin Le Normand faces a significant spell on the sidelines after being diagnosed with a traumatic brain injury following a severe head collision in his side's 1-1 draw with Real Madrid.
The Spaniard, born in France, clashed heads with opposition midfielder Aurelien Tchouameni in stoppage time of the derby match at the Estadio Metropolitano on Sunday.
He was treated on the pitch as his shocked team-mates watched on and the club have since revealed that he received 'a series of tests and was assessed by specialists'.
It has now been confirmed that Le Normand suffered a traumatic brain injury with subdural haematoma, which is bleeding triggered by a burst blood vessel near the brain, Goal.com reports.
Atletico say 'the guidelines set out in the protocol established for this type of trauma will be followed' as they look to get the centre back playing again.
Atletico Madrid defender Robin Le Normand has been diagnosed with a traumatic brain injury after suffering a severe head collision
The Spaniard (on floor, left), born in France, clashed heads with opposition midfielder Aurelien Tchouameni (on floor, right) in stoppage time of the derby match
It has now been confirmed that Le Normand suffered a traumatic brain injury with subdural haematoma
Traumatic brain injury (TBI) occurs when the brain is damaged by sudden trauma, such as a head collision or, in everyday life, banging one's head on a low doorway.
On the least severe, but most common, scale such an injury results in minor concussion or just dizziness.
Moderate TBI is defined by the NHS as 'loss of consciousness for between 15 minutes and six hours, or a period of post-traumatic amnesia of up to 24 hours'. This can lead to further residual symptoms.
The severity of Le Normand's injury has not yet been confirmed but the fact that he suffered subdural haematoma is likely to mean he will be out for a significant length of time.
Last year, La Liga announced a partnership with the AFE Group to 'develop a new concussion procedure, public awareness campaign and training resources' and 'integrate a new Video Review System tool, which allows teams to review incidents in detail and from different viewpoints'.
After announcing the partnership, Geni Martínez, Director of the AFE's Health Department, said: 'It's important to recognise a potential traumatic brain injury. In such cases, a timely withdrawal is a triumph.
'Normally, a very high percentage of the brain regenerates naturally over the next few days. The dangerous thing is to continue playing and receive another blow to the head if there had been a previous trauma that wasn't detected.'
Le Normand's collision with Tchouameni took place in the closing seconds of a typically feisty encounter between the capital city's two biggest sides.
Just minutes earlier, Angel Correa had fired home a sensational stoppage-time equaliser, rounding Real goalkeeper Thibaut Courtois to cancel out Eder Militao's 64th-minute strike.
He was treated on the pitch as his shocked teammates watched on at Estadio Metropolitano
Le Normand (left) featured in defence during Spain's Euro 2024 win this summer
Just minutes earlier, Angel Correa had fired home a sensational stoppage-time equaliser
Shortly after the opener, play was stopped after Courtois complained that fans of his former club had been throwing objects in his direction
Shortly after the opener, play was stopped after Courtois complained that fans of his former club had been throwing objects in his direction.
Both sets of players returned to their dressing rooms for a short while and, once they re-emerged, the touch paper had been well and truly lit with tackles flying in and angry words exchanged as the game reached its climax.
After Correa's leveller there was still time for Atletico's Marcos Llorente to receive a red card for a rash late challenge on Fran Garcia.