Coach Kevin O'Connell said after Sunday's 23-17 win against the 49ers that Jefferson suffered a bruised quadriceps in the contest, Tom Pelissero of NFL Network reports.
On the play that precipitated his departure late in the third quarter, Jefferson took a hit to his upper right leg that caused him to stay on the turf for a bit before going to the sideline tent and then locker room. O'Connell told Kevin Seifert of ESPN.com that Jefferson is "pretty sore," and "hopefully" the wide receiver will be day-to-day. As a result, Jefferson's status will be one to monitor closely as the Vikings gear up for a Week 3 matchup with the Texans next Sunday, especially with fellow wide receiver Jordan Addison sitting out Week 2 with a sore right ankle.