Posted by ESPN.com's Bill Williamson
UDPATE: Castillo is back in the game.
SAN DIEGO -- San Diego defensive lineman Luis Castillo is out with a knee injury.
He is currently being attended on the San Diego sideline and he is moving around well. However, Castillo, a key part of San Diego's defense, took several minutes to get off the playing field after taking the hit.
Castillo was hurt when he was blocked low by New York running back Thomas Jones.