Simpson is recovering from a back injury that he suffered before Minnesota's Week 5 game against the Tennessee Titans.
Simpson told Dan Wiederer of the Star Tribune:
Vikings coach Leslie Frazier said he held out Simpson last week because he felt he wasn't ready based on what he saw in practice.
Simpson has caught four passes for 50 yards, all coming against the Detroit Lions in Week 4, so far this season. Simpson is listed as questionable for this Sunday's game against the Arizona Cardinals.
Percy Harvin is the Vikings' leading receiver with 49 receptions for 540 yards and one touchdown. The Vikings are averaging 230.2 yards a game which ranks 17th in the league.