Original: In 1990, Sergei Makarov of the Calgary Flames became the oldest player, at age 31, to win the Calder, even though he had played for the "unofficially" professional team HC CSKA Moscow (the "Red Army" team) in the Soviet Union.
Simplified: In 1990, Sergei Makarov of the Calgary Flames became the oldest player, at age 31, to win the Calder, even though he had played professionally in the Soviet Union as a member of HC CSKA Moscow.