Becky Stuart, a personal assistant to the Favre family, said the news conference would be held at 8:30 a.m. ET at Favre's charity golf tournament at the Cottonwoods Golf Course at Grand Casino Resort in Tunica, Miss.
"You've got to get up early if you want the scoop," Stuart said.
Asked whether she knew which way Favre was leaning on whether to play or retire, Stuart said, "We've all got to find out at the same time."
But Favre's agent, James "Bus" Cook, told the Milwaukee Journal Sentinel that he was not aware that Favre would be making an announcement on his future. He said Favre indicated to him that he had not said he planned such an announcement.
The Journal Sentinel reported Packers President Bob Harlan and coach Mike McCarthy were both unaware of Favre's decision as of Friday night. McCarthy said he had not spoken with Favre this week, or heard from general manager Ted Thompson
that Favre had made a decision. The newspaper said it could not reach Thompson for comment.
Favre holds a news conference at the golf event each year, usually discussing tournament-related matters.
In a story in Friday's Green Bay Press-Gazette, Favre, 36, said that he told general manager Ted Thompson and head coach Mike McCarthy earlier this week that he may have a decision by the weekend or early next week.
"I want to do what's best, obviously, for me and my family," he said. "But regardless of what people might think, I don't want to jeopardize the future of the team. I don't want to do that. I think that the people that know me, including those in the organization, know that."
Favre, who spoke with the Press-Gazette reporter at his golf tournament, said he wouldn't want to play for anyone but the Packers, who finished 4-12 last season, Favre's only losing one in Green Bay.
Favre still feels he can play but said last season did rattle his confidence a bit.
"I had a lot of chances to pull us out of the fire last year and I didn't do it," he said.
Favre said he wouldn't return just to collect his $10 million salary or to try to break more records. If that were the case, he said, he already would have made his decision.
"That's sort of my dilemma right now. If I felt like we really could compete for the Super Bowl, I would come back. Or am I coming back just to play and to have fun, and in the process maybe we lose," he said. "Last year was no fun for the fans or for the players, and nobody wants to go through that again."
"From a coach's standpoint, you have to say the right things, that we'll be competitive and we'll win, and I truly believe Mike McCarthy will do a fine job," he said. "But really, what have we done to replace the guys that we've lost on the line?"
Favre said McCarthy isn't letting uncertainty about his star quarterback affect his preparation, which includes getting Aaron Rodgers, the team's first-round draft pick last season, ready to start.
Favre said his greatest dilemma is figuring out whether he can get up the energy to have fun, something he didn't have last season.
"It means something to come back and be there, but to come back and be that dominant player, which I wasn't last year. I never blamed it on other guys before and I won't do it now," he said. "I don't want it to be like, 'At one time he was good. He should've retired. He stuck around one year too long.' That
wouldn't be fair to anyone."
The Associated Press contributed to this report.