The Chargers have signed defensive end Luis Castillo to a new seven-year contract that will keep him in San Diego through the 2014 season. Castillo?s original rookie contract was set to expire after the 2009 season. ?Since his arrival, Luis has been played a huge role in the success we?ve had as a defense,? Chargers General Manager A.J. Smith said. ?He?s an ascending player who is committed to getting better. We?re thrilled that he?ll be a Charger for years to come.? Castillo was the second of the Chargers? two first-round draft picks in 2005. In three NFL seasons, he?s played in 36 games and started 33. Lauded for his strength, quickness and athleticism, the Northwestern University grad has posted 13 career sacks, including a career-high seven in 2006.