The Raiders signed middle linebacker Napoleon Harris on Monday in response to projected starter Kirk Morrison sustaining a dislocated left elbow Saturday night against the 49ers. Harris was the second of Oakland's two first-round selections in the 2002 NFL draft, and he started 13 games for a team that played in the Super Bowl his rookie season. Harris, 30, played for the Minnesota Vikings and Kansas City Chiefs the past four seasons, including two stints with the Vikings. Harris was included in Oakland's deal for Randy Moss