A defender, 1.89 metres (6 ft 2 in) tall and weighing 84 kilograms (185 lb), Wagner plays primarily on the half-back flank with the ability to push into the midfield.

[7] The Melbourne Football Club's list manager, Jason Taylor, praised him by noting "his last couple of years have been pretty solid...he's a left-footer and a rebounding defender, who can play on the wing and spend a bit of time in the midfield.

[8] He made his debut in the five-point loss to North Melbourne in round 3, 2016 at Blundstone Arena, where he recorded eight-disposals.

[9] After a relatively quiet debut, he recorded twenty-four disposals, six marks, five tackles and two contested marks, at seventy-one percent disposal efficiency in his second match; he polled in the Channel 7 and The Age player of the year votes,[10] and he was named as one of Melbourne's best players by AFL Media and The Age.

[16] He played the remainder of the season in the Victorian Football League (VFL) for Melbourne's affiliate team, the Casey Scorpions,[17] finishing with fourteen AFL matches for the season and a fourteenth place finish in Melbourne's best and fairest count.