Saturday, a five-time Pro Bowl selection and four-time All-Pro pick, was cut by the Colts prior to free agency as their roster experienced a major upheaval.
According to the Milwaukee Journal Sentinel, the 36-year-old received a much better offer from the Packers and had a productive meeting earlier this week with head coach Mike McCarthy.
It was widely believed that Saturday would choose to join up with Manning, who was signed by the Broncos Tuesday to a five-year, $96 million contract.
The signing fills a hole for the Packers, who lost Pro Bowl center Scott Wells to the St. Louis Rams in free agency last week.
Saturday, 36, has played 13 seasons, all in Indianapolis, where he won a Super Bowl and two AFC championships.
Undrafted out of the University of North Carolina, he has started in 188 career games, including every one over the past three seasons.
NewsCore contributed to this report.
For more coverage of the NFL, go to profootball.scout.com.
Follow me on Twitter: @RavensInsider
Want more in-depth coverage on your favorite NFL team? Click here and get started today.