That distinction goes to George Owen, Boston Bruins defenseman. He had played football while in college and when he entered the NHL in 1928 he wore the same leather helmet that he had worn in college when playing football.
Zdeno Chara
Craig MacTavish.
Craig MacTavish was the last "bare-headed" NHL player. He retired after the 1996-97 season and is currently the head coach of the Edmonton Oilers.
Willi Plett, Brad Smith, Guy Lafleur
For a while he didn't have to, but then the NHL required the use of a helmet.
You can in-fact wear a full cage in the NHL. The reason why players do not wear a cage is because it obstructs vision.
Michael Cammalleri
fiber glass
Yes he was the last NHL player, playing without a helmet. See: http://www.oilersheritage.com/history/dynasty_players_craigmactavish.html
some NHL players started to wear them in 2009 so it's likely in 2009
1979 NHL ordered all new players to begin wearing helmets, however prior players who had signed the waiver before this date were allowed to choose. So over the years after 1979 the number of players allowed to NOT wear a helmet decreased due to the older veterans leaving the game. The last person to not wear a helmet in NHL was Craig MacTavish in 1997. He played for the St. Louis Blues.
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