Tributes have been paid to rugby league player Danny Jones, who died after suffering a suspected cardiac arrest while playing for Keighley Cougars.
The Wales international 29, collapsed after being replaced during the League one game at London Skolars on Sunday.
North Wales Crusaders coach Clive Griffiths coached him with Wales and called him "the life and soul of the party" and "a really astute player".
He told BBC Radio Wales: "I was fortunate enough to have known him."
The married father of five-month-old twins was treated at the ground before being taken to the Royal Free Hospital.
Mr Griffiths added: "I'm sure that when things like this happen, that the governing body will sit up and take note and see what is best for player welfare for the future."
Bob Wilson was Wales' team manager at the 2013 World Cup and said he is "devastated" at the loss of someone he got to know well.
He last saw Mr Jones a week before his death, and said: "Danny was a real character, good fun and a great man to have in camp.
"He was someone you'd look forward to seeing when you travelled to a game."
The Rugby Football League's chief operating officer Ralph Rimmer described the loss of the "popular and talented" player as "incredibly sad".
A club statement from Keighley Cougars read: "Danny was much loved and highly respected by all at the club and in rugby league.
He was the life and soul in the dressing room, a natural leader, a true professional and irreplaceable."
John Fairclough, professor of sports medicine at Cardiff Metropolitian University, said screening would not be able to detect all the conditions that cause sudden cardiac death.
He added: "There is no magic bullet to stop people having cardiac events on the field. We can try but we can't stop it."
Wales Rugby League chairman Brian Juliff called it "shocking news".
He said: "You can't imagine what it is like for Danny's family. A fit and healthy young man, he goes away and then doesn't come back."