Harvin, who was seen on crutches on Monday, missed Wednesday's practice, and said he was a “long shot” to play against Detroit.
Michael Jenkins, second on the team in receiving yards and tied for second in receptions, is expected to play a more pivotal role. Jenkins has 26 receptions for 295 yards and one touchdown in 2012, and has rarely been used as a main-option receiver.
The loss of Harvin is a major setback for a receiving corps that have had their struggles this season. Minnesota is near the bottom of the NFL in receiving yards per game, and appear to lack depth.
Their No. 2 receiver on the depth chart is Jerome Simpson, who has eight catches for 109 yards in five games, but missed Week Six with a back injury. Head coach Leslie Frazier said Simpson has not fully recovered.
Simpson had his best game of the season at Detroit in Week Four, when he caught four passes for 50 yards. He may have to repeat that performance against a Lions secondary that allows just 214.2 passing yards per game.
Harvin's possible absence may also be missed on special teams. The Vikings may use punt returner Marcus Sherels on kick returns, or go with A.J. Jefferson, who returned kicks for the Arizona Cardinals in 2011.
Sherels and Harvin were special-team stars when the Vikings faced the Lions on Sept. 30. Harvin returned the opening kick-off 105 yards for a touchdown, and Sherels brought a punt back 77 yards for a score.
The injury comes at a terrible time for Harvin, who had been enjoying perhaps his best professional season. In nine games, has caught 62 passes for 677 yards with three touchdowns, putting him on pace for a career season.
The 24-year-old also has 16 returns for 574 yards and a touchdown.