Sheets had a season-high 28 carries for 177 yards and scored a touchdown to help Saskatchewan defeat Calgary 35-13 in the West Division final.
Teammate Jermaine McElveen was named defensive player of the week after posting a team-high five tackles and an interception.
Roughriders linebacker Diamond Ferri earned special teams honours after recording four special teams tackles and three defensive tackles in Saskatchewan's win.
Tiger-Cats receiver Andy Fantuz of Chatham, Ont., captured top Canadian honours for recording a season-high 11 receptions for 114 yards and a pair of touchdowns in Hamilton's 36-24 win over Toronto in the East final.
The Ticats and the Roughriders will meet in the Grey Cup on Sunday in Regina.