Meriweather sprained the big toe on his right foot three weeks ago in the team's Nov. 30 game against the Indianapolis Colts, leaving during the first half. He missed Washington's last two games, losses to both the Rams and the Giants.
According to ESPN's John Keim, the safety tried to take part in practice on Wednesday this week, but struggled with planting and turning his foot. He sat out practice on Thursday.
Meriweather, who signed with Washington in 2012, has had two season out of the last three shortened by injury. In his first season with the team, he missed all but one game because of injuries to his knee. Injuries and suspensions both held him out of games during the 2013 season, and he missed the first two games of the current season.
All told, injuries and suspensions have limited him to 24 of a potential 48 games during his time in Washington.
Phillip Thomas, who has played in Meriweather's stead for the last two weeks, will continue in the injured safety's place. Washington also promoted linebacker Steve Beauharnais from the team's practice squad to fill the roster spot vacated by Meriweather.
Meriweather will turn 31 in January, and will become a free agent after this season.
Washington (3-11) is currently fourth in the NFC East; Philadelphia (9-5) is second.