Born in Nigeria and raised in Brampton, Ont., Edem will enter his seventh year in the CFL. He was selected third overall by the Montreal Alouettes in the 2013 draft and also has played with the Hamilton Tiger-Cats and B.C. Lions.
The Roughriders acquired Edem in a trade with the Lions prior to the 2017 season.
Last season, the six-foot-one, 210-pound Edem had a career-high 61 defensive tackles along with two interceptions while starting in all 18 regular-season games.
For his career, Edem has 172 defensive tackles, 50 special-teams tackles, eight interceptions and five sacks.
Edem was scheduled to become a free agent on February 12.