Huddersfield Giants academy player Ronan Costello has died at the age of 17 after being injured during a game against Salford on Saturday.
He was airlifted to Leeds General Infirmary after the incident during an under-19s match.
His family said they acknowledged "that this was a tragic accident".
"We are absolutely devastated to lose Ronan so tragically and suddenly. He was a loving and caring 17-year-old lad," they added in a statement.
"He was dedicated to his family and friends and was a credit to all of his family. We are so proud of him and his achievements.
"We are all truly heartbroken and Ronan will be missed and forever in our hearts."
Rugby Football League (RFL) chief executive Nigel Wood said: "We are all incredibly saddened by news of the death of Huddersfield Giants academy player Ronan Costello.
"It is a terrible tragedy and our thoughts and prayers are with Ronan's family and friends at this time.
"We will work with both clubs involved in the game to ensure that the players, their families and friends are fully supported by the RFL Benevolent Fund and through Sporting Chance."
The Huddersfield Examiner reported it was believed the young player "sustained a serious head or neck injury during an unremarkable challenge".
The Giants have not disclosed how the teenager was injured but said in a statement: "It is with regret that Huddersfield Giants wish to inform everyone of the passing of 17-year-old academy player Ronan Costello.
"The club have been asked by the family to send their thanks for the messages of support they have received to date and have requested that all well-wishers now allow them to grieve and respect their privacy.
"The Huddersfield Giants are collating all messages, cards and tweets that they receive to pass to the family at the appropriate time."
Salford Red Devils posted this statement on their website: "The players, staff and fans of Salford Red Devils wish to extend their deepest sympathy to the family of Huddersfield Giants academy player Ronan Costello who passed away today after being injured in the under-19s game against us on Saturday.
"Our thoughts are with his family, friends and team-mates at this tragic time."
'Taken far too young'
Huddersfield's Super League rivals sent messages of support to friends and family of the young player, who had yet to feature in a first-team game.
Warrington Wolves tweeted: "All at the Wolves send our heartfelt condolences to the family and friends of Ronan Costello."
Wakefield Trinity Wildcats, who beat Huddersfield 10-2 on Sunday, said: "Our sincere condolences go out to Ronan's family, friends and team-mates at Huddersfield Giants."
Wigan Warriors posted this message on Twitter: "Our thoughts go out to the family, team-mates and friends of Huddersfield Giants under-19s player Ronan Costello."