The Manly Warringah Sea Eagles are in mourning following the sudden death of one of the club's rising stars, Keith Titmuss, on Monday.
A member of the full-time NRL squad, the 20-year-old took ill after training at Narrabeen on Monday morning.
He was transported by ambulance to nearby Northern Beaches Hospital before being transferred to Royal North Shore Hospital. He died a short time later.
Sea Eagles teammate Martin Taupau posted on Twitter that it was "absolutely heartbreaking".
Retired dual international Lote Tuqiri posted on social media: "Losing kids in the prime of their lives is so hard to fathom!"
Titmuss was a very promising young forward who had come through the Sea Eagles junior representative teams as a teenager.
He scored the match-winning try for the Sea Eagles in the 2017 NYC grand final and was named Manly's Jersey Flegg Cup Players' Player in 2019.
Sea Eagles coach Des Hasler said the club had lost a member of its family.
"We are all devastated by this news," he said.
"Keith was a very popular character amongst the playing group. He will be sorely missed but never forgotten by the Sea Eagles."
Sea Eagles CEO Stephen Humphreys said it was a very sad day.
"Our club sends its deepest condolences to Keith’s family and friends and will provide them with all of the support they need during this difficult period," Humphreys said.
GF: TRY Keith Titmuss (79th min)
"We are working with the NRL’s wellbeing team to offer support and counselling to our playing group and staff."
The Titmuss family has asked for privacy during this most distressing time.
NRL CEO Andrew Abdo has echoed the sentiments of the Manly club.
He said the NRL would offer every possible support to Keith’s family, the club and teammates.
"This is a tragic day for rugby league," he said.
"The game has lost a promising young player with the world at his feet. Keith had made it into Manly’s Top 30 for the 2021 season after coming through the club’s junior ranks.
GF: Eels v Sea Eagles (Hls)
"We will make sure Keith’s family, the club and our players receive every support they need from the game.
"We are one family and today we have lost a member of that family. On behalf of the Commission and the game I send my deepest condolences to Keith’s family."
Abdo said NRL wellbeing staff went to the Manly club on Monday afternoon to provide assistance to players and staff, including arranging grief counselling.
Rugby League Players Association chief Clint Newton added to the chorus of tributes to the young Sea Eagle.
"On behalf of the RLPA and the entire playing group, we pass on our sincerest condolences to Keith’s family and friends," Newton said.
"Our team will work with the NRL and Manly Warringah club to ensure the appropriate support and counselling is available to Keith’s family, the playing group and their respective families."