ALAMDEA, Calif. — Nick Roach, considered the glue of an Oakland Raiders defense with a lot of new parts, will not play at all in 2014. He was placed on injured reserve because of persistent concussion symptoms.

Roach was injured in the Raiders’ third preseason game on Aug. 22 against the Green Bay Packers. He returned to practice Sept. 3 and was limited, but never got through the entire concussion protocol although Roach continued to maintain he was making progress.

Roach played all 16 games for the Raiders, his first year as a full-time starter after playing with the Chicago Bears, and played every defensive snap all season.

“It’s been around 45 days since we had Nick,” Sparano said. “It’s an awful long period of time and the indications at that point weren’t getting a whole lot better.”

Roach’s absence will make Miles Burris the middle linebacker, health permitting, for the remainder of the season. Burris was originally competing with Sio Moore on the weak side before moving to the middle when Roach was hurt.

“He’s still going to be around and he’s going to be a big part of this team,” Sparano said. “Nick’s got a great football mind. He sees a lot of things people can’t see on the field, so that’s going to be big.”