It is named after Bill Masterton, the only player in NHL history to die as a direct result of injuries suffered during a game.
The winner is selected by a poll of the Professional Hockey Writers' Association after each team nominates one player in competition.
The trophy is named in honor of the late Bill Masterton, a Minnesota North Stars player who died on January 15, 1968, after sustaining an injury during a hockey game.
A US college standout at Denver University, Masterton had briefly played in the Montreal Canadiens organization before giving up his professional dreams and taking a job as an engineer at Honeywell in Minneapolis.
During his spare time, he played senior amateur hockey including for the US national team, where he was scouted by the expansion North Stars and became the club's first contracted player.