SAN DIEGO ---- The Chargers traded third-string quarterback Charlie Whitehurst to Seattle on Wednesday, a team source said, gaining a significantly higher second round draft pick in exchange for a player who hasn't thrown a pass in four NFL seasons.

The teams swapped second-round picks in next month's NFL draft, and the Chargers will also receive Seattle's third-round pick in next year's draft, said the source, who spoke on condition on anonymity because the Chargers have not announced the trade.

By trading Whitehurst, a third-round pick in 2006, the Chargers moved up from the 60th overall pick to No. 40. They also now have three third-round picks in 2011.

Whitehurst was a restricted free agent initially given a third-round tender by the team. He visited Arizona and Seattle in hopes of moving up a depth chart, which would've been impossible in San Diego with Philip Rivers and Billy Volek on the roster. Seattle was the strongest suitor for a signal caller the Chargers were willing to part with, and reportedly signed Whitehurst to a two-year deal worth $5 million annually after the trade was completed.

The additional selections are key for the Chargers, a team in need of impact players at several positions, including running back and nose tackle. The Chargers now draft No. 28 (first round) and No. 40, giving them a pair of legitimate opportunities to shore up problem spots.

Scott re-signs

Ian Scott re-signed with the Chargers, locking up another piece of last season's defensive line rotation.

The 6-foot-3, 315-pound veteran played the final 13 games of the season and made eight starts at nose tackle. He signed with the team last offseason but was released in training camp due to a knee problem. He had surgery and was signed shortly after he recovered, a period that coincided with an injury plague along the Chargers' defensive line. Terms of the deal were not disclosed.

The Chargers re-signed another of their restricted-free-agent defensive linemen, Alfonso Boone, earlier this month.