(CNN)Brazilian football player Alex Apolinario has died at the age of 24, his club FC Alverca said in a statement Thursday.
Alverca said Apolinario collapsed in the 27th minute of the club's Portuguese third division match against UFC Almeirim on Sunday, after apparently suffering a cardiorespiratory arrest.
"It is with deep sadness that we report, in accordance with the information provided by the medical staff of the Vila Franca de Xira Hospital, the passing by brain death of our athlete Alex Sandro dos Santos Apolinário, this morning," Alverca tweeted on Thursday.
"FC Alverca Futebol SAD will provide all the necessary support to his relatives. At this time of mourning all of FC Alverca activities are canceled."
According to the United Kingdom's National Health Service, brain death is "when a person on an artificial life support machine no longer has any brain functions."
In a statement on Instagram following the incident on Sunday, Alverca said Apolinario was attended to with a defibrillator by the club's health professionals.
"Firstly, we would like to thank the Firefighters and Ambulance (Services), who quickly arrived on the stadium's pitch and took care of our player," Alverca said.
"We also want to thank the support provided by all athletes and staff at UFC Almeirim in this very delicate moment which we've been through and are experiencing today."
Apolinario came through the youth ranks of Brazilian club Cruzeiro and made a handful of first team appearances before his move to Portugal.
The promising young footballer scored for Alverca in a famous Portuguese Cup upset against first division side Sporting CP back in 2019.