Despite being a 3-4 defensive end, Castillo would be a true replacement as a 4-3 under tackle as the Chargers decide to move forward with their younger options. While the Carolina Panthers have young options at DT also, they severely lack another verteran presence on the line, and someone who can get them through their early woes in the wake of Andre Neblett's suspension.
Castillo started 30 games for Ron Rivera while in SD, and amassed 51 tackles, and 4.5 sacks over this time-- solid numbers for a 3-4 DE. Thus far we've seen Rivera have a penchant for bringing in former Chargers, and it's not a huge stretch to imagine the Panthers will have serious interest in the 28 year old DT. Unlike the throngs of former players to make the move to Carolina, it's likely the Panthers will have some competition for Castillo's services as Darin Gantt reports that last season both the Kansas City Chiefs, and New England Patriots had interest in his services, which Gantt postulates could indicate there is a market for the 290 lb defensive lineman.
Missing almost the entire season last year with a broken leg, Castillo had an effective 2010 season in which he ranked in the top 50 among linemen in defensive stops, and run stopping (per Football Outsiders). On the surface this seems perfect, and digging a little deeper it still seems perfect.
Carolina Panthers fans: Is there any reason you think the team should steer clear of Castillo?