Washington cleared waivers Saturday and was sent outright to High-A Everett.
Washington was added to the Mariners' active roster Tuesday to serve as emergency bench depth on short notice, but he'll now return to High-A and give up his spot on the 40-man roster. The 26-year-old outfielder is slashing .203/.296/.419 across 170 plate appearances at Everett this season and could make a push to reach Double-A by the end of the year.