The Saints promoted Arnold to the active roster from the practice squad Saturday, Mike Triplett of ESPN.com reports.
Arnold's spot on the 53-man roster comes with Jared Cook (ankle) ruled out for Week 7. The team waived Brian Parker to make room for the Wisconsin-Platteville product on the active roster. Last season, Arnold caught 12 passes for 150 yards and a touchdown across 10 games for New Orleans.