Washington also placed right-hander Mason Thompson on the 60-day injured list. Thompson is coming off Tommy John reconstructive elbow surgery.
Sims, 30, was 1-6 with a 4.38 ERA in 58 relief appearances last year for Cincinnati and Boston, which acquired him in a July 30 trade. The right-hander is 22-19 with a 4.50 ERA and 12 saves in eight major league seasons with Atlanta (2017-18), the Reds (2018-24) and the Red Sox. He has 353 strikeouts in 306 innings.
