The Raiders did not tender a contract offer to Barnes before the start of free agency, making him an unrestricted free agent. But the team confirmed he is coming back for a second season.
Barnes signed a one-year deal last year to come to Oakland after four years in Jacksonville. He was expected to compete for a starting left tackle spot with Mario Henderson, but broke his left ankle in training camp. He appeared in just six games last season, appearing mostly on the right side of the line.
Henderson allowed an NFL-worst 10½ sacks last season. Last year's starting right tackle Cornell Green is an unrestricted free agent. Green committed 12 penalties and allowed 6½ sacks in 12 games.
"We are incredibly excited to add Kevin to our coaching staff," coach Tom Cable said. "He had a long and successful playing career and earned the respect of every team he joined along the way and we are fortunate to have him here."
Ross played defensive back for 14 seasons with Kansas City, Atlanta and San Diego. He was a two-time Pro Bowl selection and recorded 38 career interceptions.
The Raiders previously had hired Clancy Pendergast for the position to replace the retired Willie Brown. But Pendergast left after less than two weeks to take over as defensive coordinator at California.