Downs was designated for assignment by the Nationals on Tuesday.
The Nats needed to clear out 40-man roster space in order to finalize their one-year agreements with both Nick Senzel and Dylan Floro. Downs ranked as a top-100 prospect a few years ago, but he's slashed just .182/.260/.273 in 50 career plate appearances at the major-league level and posted an underwhelming .236/.358/.379 batting line across 51 games last season with Triple-A Rochester.