Meanwhile, the Los Angeles Rams announced they will hold their team meetings from home Wednesday after an unidentified player tested positive for coronavirus Tuesday night.
Washington also placed injured defensive lineman Matt Ioannidis on the list after announcing a positive test.
The Raiders put Ferrell and Joyner on the list Tuesday, joining linebacker Cory Littleton, who tested positive last week, and right tackle Trent Brown, who tested positive last month.
Los Angeles center Brian Allen was the first NFL player to confirm he had tested positive for coronavirus back in April.
A person with direct knowledge of the situation said the player who tested positive did not travel with Washington for its game at Detroit last weekend.