His club confirmed on Sunday morning that Johnson passed away following a “freak accident” in their Challenge Cup fixture against Sheffield Steelers.
The game was stopped in the 35th minute as the 29-year-old American received emergency treatment from paramedics on the ice. He was later taken to Sheffield's Northern General Hospital.
Nottingham Panthers said: “The Nottingham Panthers are truly devastated to announce that Adam Johnson has tragically passed away following a freak accident at the game in Sheffield last night.
“The Panthers would like to send our thoughts and condolences to Adam’s family, his partner, and all his friends at this extremely difficult time.
“Everyone at the club including players, staff, management and ownership are heartbroken at the news of Adam’s passing.
“Our thoughts are also with the fans and staff of both clubs, especially those who attended or were following the game, who will be devastated following today’s news.
The Nottingham Panthers are truly devastated to announce that Adam Johnson has tragically passed away following a freak accident at the game in Sheffield last night. pic.twitter.com/lhSOkDu03Q
— The Nottingham Panthers (@PanthersIHC) October 29, 2023
“The Panthers would like to thank everyone who rushed to support Adam last night in the most testing of circumstances.
“Adam, our No47, was only an outstanding ice hockey players, but also a great team-mate and an incredible person with his whole life ahead of him. The club will dearly miss him and will never every forget him
“We ask that the privacy of Adam’s family and friendly, and everyone at the club is respected at this difficult time as we all seek to come to terms with our grief.
“Rest in peace, Adam.”
Johnson previously played in the NHL, playing 13 games for the Pittsburgh Penguins.
He moved to the Swedish Hockey League for the 2020-21 season before spells with the Ontario Reign and the Lehigh Valley Phantoms in the American Hockey League.
Johnson played for Augsburger Panther in Germany before signing for the Nottingham Panthers in August.