Espanyol's captain, Daniel Jarque, has died after he suffered a heart attack during a training session in Italy with the club.
Club doctors and Italian paramedics tried to revive the 26-year-old without success.
Jarque joined Espanyol in 1995 as a 12-year-old, and has been a regular in the Catalan side since he made his debut in 2002. He was named as captain only this summer.
"Tragedy struck Espanyol and the family of Dani Jarque this evening. The player died from a cardiac arrest," said a club statement.
"The doctor carried out CPR on the player and used a defibrillator, which showed that the arrest was non-responsive.
"RCD Espanyol, broken with pain, wish to put themselves at the absolute disposition of the family of our captain Dani Jarque, to whom go our warmest thoughts."
"We are returning to Barcelona on Sunday but we can't come back with the coffin because they have to do an autopsy to confirm the cause of death," added club director German de la Cruz.
"The players are destroyed. One minute he was there with them, and the next he's gone. It's terrible."
The president of city neighbours Barcelona, Joan Laporta, offered his club's condolences.
"We are filled with extreme dismay at this tragic event which we deeply regret," he told the Barcelona club website.
"We are all in mourning. I want to send, on behalf of FC Barcelona, our deepest sympathies to RCD Espanyol for the painful loss of their captain Dani Jarque, and to his family."
The death will stun Spanish soccer. In 2007, 22-year-old Antonio Puerta passed away after he too had suffered a heart attack whilst playing for Sevilla.
And over the last 10 years, the condition known as "Sudden Death Syndrome" has claimed the lives of professionals and amateurs alike.
There are many theories as to what causes the syndrome. Some experts feel that the players are being pushed to their limits as training techniques have evolved. Others feel that sports drinks have contributed also.
While many feel that players are now taking far too many supplements, and that their systems cannot handle the medication on top of the high intensity training.
A recent report on Sudden Death in Sport tells us;
Most sudden deaths in sport are caused by cardiovascular conditions. The cardiovascular benefits of exercise are well-established, and epidemiology studies suggest that long-term exercise programmes may reduce the risk of sudden death.
A few people are at risk of serious arrhythmia or sudden death with exercise. The cause of death varies with the age of participants; congenital structural abnormalities occur in younger age groups and coronary artery disease in older age groups. Identifying such abnormalities makes prevention possible.
Sudden death in sport remains uncommon, with an incidence of two cases per 100,000 subject years. Five in 100,000 athletes have a condition that might predispose them to serious cardiac problems, and of those at risk 10 percent (one in 200,000) may die suddenly or unexpectedly.
In 2005, FIFA commissioned an investigation into sudden death within sport. The report found that because young people play sport, the sudden death of one so young, often gains more media attention.
It went on to say that these deaths are in most probability caused by a "silent cardiac problem" that the person was unaware of.
There are several methods in preventing such tragedies, but the method used in Italy is the most favourable.
In 1971, the Italian Olympic Committee passed a decree that all professional sports athletes have to undergo a full medical every year.
They went on to do a study of over 33,000 athletes and found that professional athletes were twice as likely to suffer from cardiac arrest when compared to the normal populace. Most worrying, the average age of cardiac arrest death was calculated to just 23.
Hence the preventative nature of the yearly medical which should pick up on such matters.
The death of Daniel Jarque is a loss to his family and football. We wish them well in their time of grief.