Rau, a forward who was picks in the third round (No. 91) by the Florida Panthers in the 2011 NHL Draft, signed a one-year, two-way contract with the Minnesota Wild on July 1, 2017.
Rau first established himself at Eden Prairie High, scoring 69 points in 25 games of his senior year to be named the Mr. Hockey Award recipient as Minnesota's finest player. He stayed home to play college hockey at the University of Minnesota. Rau was captain for the 2014-15 season, finishing with 41 points (20 goals, 21 assists) in 39 games to help the Golden Gophers win the Big Ten Conference championship. He finished with 164 points (67 points, 97 assists) before signing a three-year contract with the Panthers on March 29, 2015.