The fourth-year pro played in nine games last season but was unable to survive the final roster cutdown in September. He fills the void left when the Packers released Smith on Tuesday. Smith became expendable in part because of the return of injured nose tackles Grady Jackson and James Lee and partly because the Packers needed an extra defensive back.
Fuller is a security blanket should the Packers' wounded defensive backs be held out of Sunday's game.
Sharper hinted Wednesday that he might miss the game and then use the upcoming bye week to give his ailing left knee two full weeks to rest so he's ready for what suddenly looks like an intriguing second half to the season.
"I have to be smart about it," Sharper said. "I'm not going to go out there and jeopardize and be hobbled for the whole rest of the season when those games are going to be really, really important."
Nonetheless, Sharper was hoping he could test the knee on Friday. He sprained the posterior-cruciate ligament in his left knee while batting down a pass intended for Keyshawn Johnson in the end zone during the first quarter Sunday. He sat out the remaining three quarters.
Harris, meanwhile, suffered a sprained posterior-cruciate ligament in his left knee during the third quarter of the Dallas game but was able to finish the game.
"He's going to play," Sharper said. "I'm not going to even think about Al not playing."
Neither Harris nor Sharper practiced Wednesday, and the same goes for starting quarterback Brett Favre. Favre's throwing hand was bruised and sprained when he braced himself for a hit from Dallas La'Roi Glover during the second quarter. Favre's hand smacked into Glover's helmet.
Favre certainly was no worse for wear against Dallas, guiding six consecutive scoring drives to lead Green Bay's second consecutive resounding victory.
The bruise has worsened since the game, however. The injury doesn't affect Favre's throwing as much as it does receiving the snap from center Grey Ruegamer. Because of that, Packers coach Mike Sherman will spare Favre from taking the center-quarterback exchange during today's practice.
Favre is listed as probable (75 percent chance of playing) for Sunday's game.
In other injury news from a short initial injury report:
— Marco Rivera: The Pro Bowl right guard ditched the crutches he was using Monday and expects to play Sunday. Rivera didn't practice Wednesday, nor will he today, and is listed as questionable. If he can't start, right tackle Mark Tauscher would move to guard and be replaced by Kevin Barry.
— Ahman Green: The Pro Bowl running back was named NFC Offensive Player of the Week after dissecting the Dallas defense. Because of his 163-yard performance, Sherman will duplicate last week's schedule for Green. Green did not practice Wednesday and will not practice today due to a sore Achilles' tendon. He is listed as probable.
"Certainly, holding him back last week didn't seem to hurt him in the game," Sherman said. "So we'll probably use that same formula."
— Aaron Kampman: The starting power end was held out of Wednesday's practice with a sprained ankle. He is listed as probable.