Williams, who was acquired by the Packers and put on their practice squad after he was waived by the Baltimore Ravens on Monday, could become the first in NFL history to play for two different teams in the same postseason.
Williams, 37, had three tackles in the Ravens' 17-3 AFC divisional playoff loss at the Buffalo Bills last week.
Williams previously played for the Packers from 2007 to 2014 and 2018 to 2019, and he had a key role in the team's run to Super Bowl XLV with interceptions in playoff games versus the Philadelphia Eagles and Atlanta Falcons.
"It's special," Packers quarterback Aaron Rodgers said of the team's decision to sign Williams this week. "He's one of those teammates you just love playing with over the years. He's such a professional. The way he takes care of himself, he looks amazing. He looks like he could go out and play 70 plays for us. I'm not sure if he's going to or not; I hope he does, because he's still so talented. But he's one of those special guys, special personalities."
"You think about the 2010 run -- he ended a game in Philly; [he] basically gave us a huge jolt in the divisional round [against Atlanta] with his pick-six. Still one of my favorite moments in all the moments in that is watching him pick that ball off and run down the sidelines with Nick Collins to put us up 14 going into half. So, it's fun. I wish we did this every year."
Green Bay might need extra depth in the secondary because of the uncertain status of starting cornerback Kevin King, who didn't practice Friday due to a back injury and is listed as questionable.
The Packers also elevated defensive lineman Brian Price and cornerback KeiVarae Russell from the practice squad to the active roster for game day. In other moves, they signed punter Ryan Winslow to the practice squad and released running back Dexter Williams from the practice squad.
ESPN's Rob Demovsky and The Associated Press contributed to this report.