The person, who requested anonymity because of the sensitivity of the subject, said Packers officials believe Vikings offensive coordinator Darrell Bevell had discussions with Favre that would violate league rules. Presumably, such discussions would include the possibility of Favre leaving the Packers for their NFC North rivals in Minnesota.
"They feel like Favre had something (in place), and that's why he was so anxious to get his release all of a sudden," the person said.
Favre and Bevell are friends going back to Bevell's days as an assistant in Green Bay. The three-time MVP retired in March, but has since said that he wants to return, which has led to a messy back-and-forth with Packers GM Ted Thompson.
The Packers told The AP that they were ready to welcome Favre back to the team later in March when Favre expressed reservations about his decision to retire, only to be assured by the quarterback that he was finished.
Favre has said that he felt pressured by the Packers to retire and now has been told that if he returns to Green Bay, he wouldn't necessarily get the starting job back.
The team told the league that it believes an investigation of phone records will show more than "normal contact" between Favre and Bevell, even before he formally asked for his release to play for another team.
Bevell was not available to comment on Thursday and neither were any other Vikings officials, Hagan said.
AP Sports Writer Chris Jenkins in Milwaukee contributed to this report.