The Oakland Raiders have re-signed defensive coordinator Jason Tarver to a new contract, the team announced.

The Raiders ranked 22nd in total defense this past season.

Tarver returns after the Raiders improved to 18th in total defense in 2012, nine spots higher than his first year as defensive coordinator.

The Raiders did a two-year contract extension for assistant head coach-offensive line coach Tony Sparano after the season.

Special-teams coach Bobby April is returning, too.

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Aaron WIlson covers the Ravens for The Baltimore Sun.