Sam Bradford’s knee is flaring up again and causing issues for the Minnesota Vikings. And, according to Vikings head coach Mike Zimmer, the quarterback’s availability for next week still remains cloudy.

From Chris Tomasson of the Pioneer Press:

“It’s day to day, and we’ll go from there,” Zimmer said.

Zimmer was talking about Bradford and his status for Minnesota’s Week 4 matchup with the division rival Detroit Lions at home. Bradford was ruled out of Week 3, leaving the quarterbacking duties to backup Case Keenum, who did well in their 34-17 win over the Tampa Bay Buccaneers. Keenum operated smoothly under center opposite the Bucs, going 25 of 33 for 369 passing yards and three touchdowns without an interception while boasting a perfect passer rating.

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Bradford also sat out Week 2’s contest against the Pittsburgh Steelers after hurting his left knee in the season opener versus the New Orleans Saints. While tests prove that there is no structural damage in Bradford’s troublesome knee, it’s just prudent on the part of the Vikings to keep the former Oklahoma Sooner off the field until he is truly 100 percent healthy and ready to play his best.

Given Bradford’s current condition, Keenum should prepare for the Detroit showdown as if he’s going to start.