Fisher is doubtful on the initial injury report with a broken rib, which kept him out of the last Sunday's game against Pittsburgh. Coach Mike Sherman wasn't optimistic Wednesday that Fisher would be ready by the weekend.
"A day-to-day, week-to-week issue," Sherman said. "When the doctors give me the green light on Tony, then I'll know he can play. They have not done that as of yet."
Samkon Gado will become the Green Bay Packers fifth starting halfback of the season this Sunday against the Atlanta Falcons. ReShard Lee replaced Fisher in the starting lineup for Sunday's 20-10 loss to Pittsburgh but was quickly yanked by Sherman after fumbling away the football on his second carry.
Gado, who was signed to the practice squad only three weeks ago, came off the bench and responded with 26 carries for 62 yards, both single-game highs this season for the Packers' struggling run game.
Fisher had been elevated from a role of third-down specialist to the featured spot after Ahman Green and Najeh Davenport sustained season-ending leg injuries last month.
Lee will spell Gado on early downs, and Walt Williams will continue in his role as the third-down back.
--The interior of the defense, which has been a strong suit for the improved unit thus far, took a hit when Williams suffered a strained right calf in the second half of Sunday's game.
Williams still was walking with the aid of crutches Wednesday and has been ruled out for the upcoming contest.
"He'll be out for this ballgame," Sherman said. "Calf strains take a little bit of time. Certainly, three days is not enough time for that just yet," Sherman said. Williams, an athletic second-year player, has been a key contributor as part of first-year coordinator Jim Bates' liberal rotation on the line.
Williams backs up Cullen Jenkins and ranks third among the team's interior linemen with 25 tackles, including two sacks.
Others who are hobbled
-- Wide receiver Robert Ferguson did some individual drill work in practice Wednesday for the first time since he sustained a torn lateral collateral ligament in his left knee Oct. 23.
Ferguson took part in a mock team drill, but wasn't involved in other team drills in practice, and is listed as questionable to play Sunday.
"That will be a late-week decision on Robert in regard to his availability against the Falcons," Sherman said.
-- Tight end David Martin didn't practice Wednesday and is questionable for Sunday's game. The top backup to Bubba Franks has been nursing a strained groin that has kept him out of the last two games. He did not practice on Wednesday.
-- Linebacker Na'il Diggs was not listed on the injury report for the first time since he sustained a torn medial collateral ligament in his right knee Oct. 3. He is prepared to reclaim his starting strongside spot Sunday. Diggs has played in only two games this season, having missed the first two because of a torn MCL in his left knee sustained early in the preseason.
-- Center Mike Flanagan didn't practice Wednesday but is probable for Sunday's game. Flanagan is coping with some residual pain in his groin area after he underwent surgery Oct. 5 for a sports hernia. Flanagan has started the last two games.
-- Offensive left tackle Chad Clifton also was held out of Wednesday's workout but is probable for Sunday. Clifton aggravated an ankle injury in the last game.
-- Saying he felt lethargic Wednesday, quarterback Brett Favre was given the day off from practice. Favre said afterward he will be back on the field Thursday.