Nall relieved Favre six times in his career between 2003 and 2005. He went 23-of-33 for 314 yards with four touchdowns and no interceptions in those appearances.
Favre is expected to start his 250th consecutive game against the Oakland Raiders on Dec. 9, continuing his record streak that started in 1992.
The 38-year-old Favre, a three-time MVP, was knocked out of the Packers' 37-27 loss at Dallas on Thursday with elbow and shoulder injuries.
Rodgers came in and played well the rest of the way, finishing 18-of-26 for 201 yards and a touchdown.
But the Packers decided to sign Nall, after joining a growing trend of teams that carried just two quarterbacks on their 53-man roster.
To make room for Nall, the team released safety Marviel Underwood for the second time this season. He is trying to come back from a knee injury he suffered in the final preseason game last year.
Copyright 2007 by The Associated Press. All Rights Reserved