Raiders fans panicking about having only three defensive starters Tuesday can relax. First off, the first game is still six months away, and second, they now have possibly six defensive starters. Oakland signed free-agent linebacker Kaluka Maiava to a $6 million, three-year contract Wednesday. The Raiders also signed defensive tackle Pat Sims and defensive end Jason Hunter. Maiava, 26, started 13 games last season for Cleveland with 30 solo tackles, two sacks, two forced fumbles and three passes defended. A 5-foot-11, 229-pounder, Maiava played 50 games over four seasons with the Browns. He was a fourth-round pick from USC. There, he was a member of a Trojans linebacker group that also had NFL-ers Brian Cushing, Clay Matthews and Rey Maualuga. Sims played eight games last season for Cincinnati after coming back from a hamstring injury. Hunter, who was with Denver for three seasons, sat out last year with a triceps injury. "We're excited to add three veterans through free agency, helping to create depth and competition on defense," said general manager Reggie McKenzie, who took chances on players coming off injury last year as well. "We'll continue to add free agents as the opportunity surfaces."