The Raiders used their franchise tag Thursday to keep linebacker Kamerion Wimbley under contract for 2012. Oakland originally hoped to use a $3.5 million buyback option to keep Wimbley under contract for next season for just over $4 million. But Wimbley's agent, Joe Linta, said the NFL determined that deal violated rules prohibiting base salaries rising more than 30 percent in a year. That led to the Raiders decision to use the franchise tag, which is projected to be worth about $10 million.