Wagner, who plans to hire an agent, was the highest-rated player on ESPN's board still unannounced for the July draft.
The 6-foot-9 Wagner led the Wolverines to an Elite Eight appearance and a No. 1 seed in the NCAA tournament. Wagner, 19, averaged 12.5 points, 6.5 rebounds and 3.0 assists on 47% shooting for Michigan. Wagner is considered one of the best defenders in the draft.
A native of Germany, Wagner is the younger brother of another former Michigan first-round pick, the Orlando Magic's Moe Wagner.