In 2011, he had a breakthrough year in the VFL, winning the Zebras' best and fairest award, and becoming noted as one of the league's top midfielders.
[3] While playing VFL football, Magner made a living as a highway construction worker.
He was promoted to the senior list as a nominated rookie prior to the start of the season,[5] and made his AFL debut in Round 1, 2012, against the Brisbane Lions,[3] where he polled two Brownlow votes for his 23 disposals, which featured two goals with his first two kicks.
He followed this up with another strong performance against West Coast the next week as one of Melbourne's best, with 32 disposals in a 108-point loss.
He later expressed frustration with the way he was treated by the club in his second season; he believed that his VFL form had warranted regular senior selection, but that the club had already decided it would delist him under youth policy, yet the coaches refused to be up-front and honest with him about its intentions, leaving him confused about whether he had any hopes of senior selection.