As expected, the Carolina Panthers will announce that Ron Rivera will be the fourth head coach in franchise history.

The official announcement is expected to come later on Tuesday.

Rivera, 49, has been the San Diego Chargers defensive coordinator since midway through the 2008 season. San Diego ranked 25th in total defense in 2008, but improved to 16th in 2009 before leading the NFL in total defense (271.6 yards allowed per game) and pass defense (177.8 yards allowed) in 2010.

Rivera played nine seasons for the Chicago Bears, and began his coaching career with the Philadelphia Eagles, coaching linebackers for five seasons before returning to the Bears as defensive coordinator in 2004. Rivera joined the Chargers as a linebackers coach in 2007 before he was promoted to defensive coordinator in 2008.

The Panthers were the ninth team Rivera has interviewed with for head coaching positions over the last six seasons.