Washington was signed to New Orleans' 53-man roster Friday, Ian Rapoport of NFL Network reports.
Washington joined the Saints' practice squad after being let go by the Lions at roster cutdowns. The 24-year-old had 110 carries for 309 yards (2.8 average) in two seasons with Detroit. Alvin Kamara has been the heavy workhorse with Mark Ingram suspended through Sunday's game against the Giants, and Washington's addition is unlikely to alter that significantly.