Rinehart started 10 games last season, his first with the Chargers. He missed some time due to injuries.
The 28-year-old has made 31 career starts in 42 games with Washington, Buffalo and San Diego. He was originally selected by the Redskins in the third round of the 2008 draft.
The Chargers now have their entire starting offensive line from last season under contract for 2014.