SAN DIEGO - The San Diego Chargers have placed left tackle Jared Gaither on injured reserve, ending an unproductive season for a player expected to shore up a shaky offensive line.

Gaither played in only four games this season. He missed almost all of training camp and the first three games with a back injury. He injured his groin late in a loss at New Orleans and played in only two games since.

Undrafted rookie Mike Harris has filled in.

Gaither was signed off waivers after Marcus McNeill was hurt late last year, and played well in the final five games. The Chargers gave Gaither a four-year, $24.5 million contract in March.

Philip Rivers has been under siege most of the season because of the line's poor play. Adding to San Diego's woes was the retirement of left guard Kris Dielman due to a concussion.