The 6-foot-1, 230-pound Rau made three tackles in four games last season.
The Eagles signed Rau as an undrafted free agent from Portland State in 2012, and the Folsom, Calif., native spent the first 13 weeks of the season on their practice squad. He was elevated to the active roster on Dec. 8, 2012.
During his college career, Rau played in a school-record 43 games, and led Portland State in tackles in each of his final three seasons. He tallied 287 career tackles, and as a season in 2011, Rau registered a career-best 89 stops, as well as three sacks, and also forced a fumble. As a junior in 2010, Rau made 83 total tackles.