Unsigned is no longer an adjective that can be attached to San Diego Chargers running back Darren Sproles’ name. The all-purpose back and kick returner inked his $6.621 million franchise tender today, according to John Clayton of ESPN.com. That base salary figure is now guaranteed for next season. By signing the tender, Sproles is now required to attend mandatory offseason activities as well as training camp. Last season, the 5'6,” 181-pound former Kansas State standout gained 330 rushing yards and scored one touchdown, catching 29 passes for 342 yards and scoring five touchdowns. He averaged 5.4 yards per carry and 11.8 yards per reception, finishing eighth in the league in kickoff return average (26.0) and punt return average (11.3). UPDATE: The Chargers announced that they have signed Georgia cornerback Ramarcus Brown and cut cornerback Grant Mason.