ALAMEDA (AP) — The Oakland Raiders added some needed help at cornerback, agreeing to contracts with free agents Rashaan Melvin and Shareece Wright on Friday.A person familiar with the move said Melvin got a one-year, $6.5 million contract. The person spoke on condition of anonymity because the terms were not announced. ESPN first reported the signing.Wright announced his plans to join the Raiders on his Instagram account .The Raiders also added some depth to the defensive line with former San Francisco 49er Tank Carradine saying he will stay in the Bay Area and join Oakland.Oakland has lost the three cornerbacks who played the most last season, releasing Sean Smith and David Amerson, and losing TJ Carrie to Cleveland in free agency.