The author illustrates that while violence and even fist-fighting are condoned to a certain extent in NHL games, there are certain conventions players adhere to when they use violence and aggression. A deconstruction of the incident in question involving Vancouver's Todd Bertuzzi and Colorado's Steve Moore showed that Bertuzzi stepped outside of these conventions during his attack on Moore by sucker punching Moore instead of squaring up to him and openly challenging him by throwing down his hockey stick and removing his gloves. There is thus a clear, although unspoken line between sanctioned and unsanctioned violence in NHL games. Legal aspects of the incident are examined and psychological explanations are offered regarding why Bertuzzi attacked Moore seemingly without provocation and in an unsanctioned manner. Reversal theory is used to explain Bertuzzi's act of unsanctioned violence, which holds that violence in team sports takes place within a psychological bubble that allows players to experience violent plays as pleasant while hampering the perception of risk or danger. The author considers whether NHL hockey should change and suggests that clear guidelines on the use of aggression could improve the game of hockey in much the same way such guidelines have improved other professional sports. Table, references