 On January 13 , 1968 , North Stars ' rookie Bill Masterton became the first and , to date , only player to die as a result of injuries suffered during an NHL game . Early in a game against the Seals , Masterton was checked hard by two players , Ron Harris and Larry Cahan , causing him to flip over backwards and land on his head . He was rushed to hospital with massive head injuries , and died there two days later . The National Hockey League Writers Association presented the league with the Bill Masterton Memorial Trophy later in the season ; the trophy is awarded annually to the player who best exemplifies the qualities of perseverance , sportsmanship and dedication to hockey . Following Masterton 's death , players slowly began wearing helmets ; starting in the 1979 – 80 season , the league mandated that all players entering the league wear them . 
