ALAMEDA, Calif. (AP) - The Oakland Raiders have signed linebacker Kaluka Maiava, defensive tackle Pat Sims and defensive end Jason Hunter to free agent contracts as they attempt to shore up a struggling defense.

A day after losing three of the team's most productive defenders from last year when Oakland released defensive back Michael Huff and lost linebacker Philip Wheeler and defensive lineman Desmond Bryant in free agency, the Raiders started the rebuilding process.

Oakland has only four returning defensive starters under contract in safety Tyvon Branch, linebacker Miles Burris and defensive linemen Lamarr Houston and Tommy Kelly. But Kelly could still be released as a salary cap casualty this offseason.