The San Diego Chargers' offensive line has been a pleasant surprise during the first two weeks of the season. The new-look unit has given Philip Rivers the necessary time to be a dominant quarterback again.

One of the reasons for San Diego’s success on the line is first-round pick D.J. Fluker, who has stepped in and made an impact at right tackle. But the Chargers may be without him for Sunday's game at Tennessee.

Fluker did not practice Thursday because of a concussion he suffered in practice the day before. Because of league protocol, it may be difficult for Fluker to pass all of the tests necessary for him to be able to play Sunday. Mike Harris, a starter at left tackle last season, would start if Fluker can’t play.

Meanwhile, linebacker Donald Butler was limited in practice Thursday after sitting out Wednesday with a groin injury. The team thinks he can play Sunday. Rookie linebacker Manti Te’o practiced on limited basis for the second straight day after being out nearly six weeks with a foot injury. Still, it may be a long shot for him to play Sunday.