Vikings linebacker Jason Trusnik might have to learn quickly this week.

Trusnik was signed on Tuesday and took part in his first practice Wednesday, replacing injured linebacker Audie Cole, placed on season-ending injured reserve with a fractured right ankle.

Also missing Wednesday, starting linebackers Anthony Barr (hand) and Eric Kendricks (ribs). Their availability for Sunday’s game at Oakland is uncertain.

“I feel I have a good understanding of what they’ve been doing,” said Trusnik, a nine-year veteran. “I can say that if they need me this week, I’ll be ready.”

Defensive tackle Sharrif Floyd, who has missed the past three games with knee and ankle injuries, and cornerback Terence Newman, who suffered a concussion against St. Louis, were among those who practiced on a limited basis.

Wearing a knee brace, Floyd vowed he’ll be ready to face the Raiders.

“I’m already conditioned,” he said. “I felt great (practicing). Everything went good. No problems.”

Also practicing on a limited basis were quarterback Teddy Bridgewater (concussion) cornerback Marcus Sherels (shoulder), defensive tackle Linval Joseph (foot) and defensive end Justin Trattou (ankle).

Trusnik played for the New York Jets, Cleveland and Miami before being cut by Carolina on Sept. 5. He and 10-year man Chad Greenway are the only Minnesota linebackers who have played more than two NFL seasons.

Trusnik’s linebackers coach with the Dolphins in 2012-13 was Vikings defensive coordinator George Edwards.

“He kind of knows the system, good special teams player, played a number of spots for (Miami),” head coach Mike Zimmer said. “We worked him out a while back and told him to stay ready.”

Trusnik said he worked out with Minnesota two weeks ago.

“When I got the call back, I was pretty excited,” he said. “They’re doing good things, winning. So I was excited to be here and be part of something special.”

Follow Chris Tomasson at twitter.com/christomasson.