Wallin, 25, returns to the Thunder for the 2016-17 season after he collected 11 points (4g-7a) in 27 games with the team over the past two seasons. The Yardley, Pa. native appeared in 47 games with the Rapid City Rush during the 2016-17 season, where he amassed 31 points (12g-19a), which ranked sixth amongst all Rush forwards. Wallin also appeared in nine postseason games with Adirondack during the 2016 Kelly Cup Playoffs and collected one assist.
From 2015-17, Wallin also skated in 43 games in the SPHL with the Peoria Rivermen and collected 32 points (14g-18a). Prior to beginning his professional career, Wallin skated for four seasons with UMass-Lowell. With the Riverhawks, he skated in 138 games, amassing 50 points (16g-34a). Wallin helped UMass-Lowell to a Frozen Four appearance in 2013.