During his junior career, Tambellini earned MVP honours in the British Columbia Hockey League (BCHL), while also leading the Chilliwack Chiefs to a Fred Page Cup as league champions and a Doyle Cup as Pacific regional champions. In 2002, he joined the college ranks with the Michigan Wolverines of the Central Collegiate Hockey Association (CCHA). Over three seasons, he won two Mason Cups with Michigan as CCHA champions, while earning several individual honours, including league rookie of the year in 2003 and playoff MVP in 2005. Internationally, he competed for Canada's under-20 team at the 2004 World Junior Championships, earning a silver medal.