Kulemin, 20, finished third in the Russian Super League with 27 goals in 39 games for league champions Metallurg Magnitogorsk. The six-foot-one, 205-pounder added 12 assists and finished with a plus-minus rating of plus-17.
"Nikolai utilized his powerful skating ability and heavy shot one of the Russian Super League's most dominant goal-scorers this past season," Maple Leafs vice-president and general manager John Ferguson said in a statement. "We plan to leave him in Russia to continue his development and envision him playing a significant role in the future of the Toronto Maple Leafs."
Kulemin won a silver medal at the 2006 world junior championships, and has represented Russia twice at the world championships.