Anderson, 39, was a free agent following nine-plus seasons with the Ottawa Senators. He owns a .913 save percentage and 2.84 goals-against average across his 17-year career, but those numbers have significantly waned in recent seasons (.901 SV, 3.37 GAA since 2017-18).
The veteran netminder is a presumed replacement for Henrik Lundqvist, who the Capitals signed in October. Lundqvist is unable to play this season after undergoing successful open-heart surgery earlier this month.
Washington's starting goalie is 23-year-old Ilya Samsonov, who debuted last season with a .913 SV and 2.55 GAA in 26 appearances.