A physical and durable 12th-year pro, Jammer is the third longtime San Diego Chargers player to bolt for their AFC rivals this off-season, joining linebacker Shaun Phillips and right guard Louis Vasquez.
Jammer spent his first 11 seasons in San Diego, where he had 21 interceptions and 130 pass breakups. He was the fifth-overall draft pick in 2002 out of Texas, where he played safety.
Since becoming a starter in 2003, he's missed just three starts, opening 157 games, most by a cornerback in the NFL during that span.
Jammer had a pick-6 against Peyton Manning in Week 6 last season.
Woodson signed with Oakland last week.