In 1988/1989 season, Ron Dugay was still not wearing a helmet. I believe he was the last King player to do so. The next year Dugay played for the San Diego Gulls so if it was not him it would have to be after that season.
the year of 2012
In every contest, there is a winner and a loser.
brad marsh
Yes he was the last NHL player, playing without a helmet. See: http://www.oilersheritage.com/history/dynasty_players_craigmactavish.html
Craig MacTavish.
Brad Marsh
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.
To date, they have never won the Stanley Cup.
In 1998, when the Detroit Red Wings swept the Washington Capitals.
brad smith
Bob Shiek
I have no idea who the last five players were, but the very last one was Craig MacTavish, who is the current head coach of the Edmonton Oilers. His last season was with the St. Louis Blues in 1996/97. When he retired at the end of that season he was the last player to not wear a helmet.