Fox television's Jay Glazer reported Sunday that Favre told league investigators earlier this week he left phone messages for Jenn Sterger, who worked for the Jets in 2008 when Favre was their quarterback.
Fox did not say who provided the information. The NFL said it is not commenting on details of the investigation.
Glazer also reported that Favre denied sending Sterger inappropriate photos.
The NFL is investigating a Deadspin report earlier this month that Favre sent the racy photos to Sterger two years ago. Sterger, now an on-air personality for Versus, has not cooperated with the league yet, but her manager, Phil Reese, told The Associated Press on Sunday that could happen quickly.
"She is strongly considering it, leaning toward it," Reese said.
Asked if Favre admitted leaving the voicemails for Sterger, but denied sending any photos, Reese added:
"We're currently in the fact-gathering stage; all I'm doing is dealing with facts. Unfortunately the person in the pictures didn't also hold up their driver's license, so I'm not going to speculate as far as identity. But I'm working with people to diligently get all the facts."
Reese also has said that Sterger has had no discussions with Favre's representatives about a possible financial settlement stemming from the allegations.
Favre and the Vikings play Sunday night at Green Bay.