Veteran safety Atari Bigby was placed on season-ending injured reserve, the San Diego Chargers announced Tuesday. The seventh-year player, who injured a groin muscle in Sunday's loss to the Baltimore Ravens, was second on the team with 68 tackles. To take his roster spot, the Chargers re-signed linebacker Bront Bird, who was with the Chargers last season. The undrafted free agent had seven tackles in nine games. Also, the Chargers signed safety Sean Cattouse to the practice squad. He filled the practice squad spot that opened up when the team promoted offensive tackle Kevin Haslem to the active roster last weekend.