Forbath is questionable for the game with a groin injury and has not been ruled out. He plans to travel with the team to Green Bay, according to WRC-TV. The Redskins later confirmed the signing of Potter.
Potter was the Buffalo Bills' seventh-round draft pick in 2012. He was used in six games as a kickoff specialist that season.
The former Western Michigan Bronco spent the 2013 preseason with the Redskins, but has yet to attempt a field goal or extra point in a regular-season game.
UPDATE: To make room for Potter on the 53-man roster, the Redskins released Pat White, the team announced. NFL Media Insider Ian Rapoport reports that the team likely will bring back White if he clears waivers.