A battered Vikings secondary just took another big hit. As if the absence of cornerbacks Chris Cook and Antoine Winfield wasn't enough, now the Vikings will face Oakland on Sunday at Mall of America Field without strong safety Husain Abdullah.

Abdullah was once again on the sidelines during Friday's workout at Winter Park, still not cleared to return after suffering a concussion Monday night in Green Bay. After practice, coach Leslie Frazier declared Abdullah out for this weekend.

Frazier also stamped a questionable tag on linebacker Erin Henderson and tight end Visanthe Shiancoe, both still dealing with hamstring issues.

Other major injury notes:

  • Long snapper Cullen Loeffler was back in action during Friday's practice and will be OK to play Sunday.
  • Guard Anthony Herrera will miss his third consecutive game with a knee injury.
  • Oakland has three key players out for Sunday: running back Darren McFadden, receiver Jacoby Ford and cornerback Chris Johnson.

Sapp watch: Benny Sapp, who returned to the Vikings on Wednesday, will play Sunday against Oakland, likely to assume some nickel back responsibilities. Marcus Sherels will likely remain the starter at nickel back with Sapp working in. "Now how much he plays? That will be determined," Frazier said.

Linebacker look: With Erin Henderson questionable and E.J. Henderson still battling a chronic knee problem, the Vikings might need to keep Kenny Onatolu on call Sunday. Frazier said he'd also like to have Xavier Adibi active if possible. Frazier did note that E.J. Henderson was impressive in three days of practice this week.

"We were commenting on it yesterday when we were watching the tape from practice and he looks fresher than he has in awhile," Frazier said. "He played more like E.J. in that game Monday night. He made some good plays for us. He looks much better than he has."