The Chargers signed SS Atari Bigby (Seattle) to a two-year contract on Friday, according to a tweet by the team’s director of public relations. The contract is reportedly worth $4.5 million. Bigby fills a major hole for the Chargers with SS Steve Gregory departing to the Patriots. “(SS) is a position, when you look at our depth chart, where we are very thin,” coach Norv Turner said earlier on Friday.