Matthews captured the honour at the CFL's awards banquet in voting conducted by the Football Reporters of Canada and the league's eight head coaches.
Defensive lineman Jabar Westerman of the B.C. Lions was the finalist.
The six-foot-five, 229-pound Matthews was Winnipeg's leading receiver as a rookie, sixth overall, with 81 catches for 1,192 yards and seven TDs despite the Bombers using three different quarterbacks this season.
Westerman, a native of Brampton, Ont., was selected second overall in the 2012 CFL draft and recorded 14 tackles and four sacks for a defence that led the league in 18-of-25 categories, including sacks (47).
The CFL awards are sponsored by Gibson's Finest.