These recent remarks from GM Ted Thompson aren't too surprising. From ESPN:
"I think it's probably going to be a few years," Murphy told Packers fans during the team's Tailgate Tour, according to the Green Bay Press-Gazette. "We made that mistake when he first retired after the 2007 season. Ironically, we were going to retire his number and have a big ceremony at the opening game that next season against the Minnesota Vikings.
"Little did we know he'’d end up playing that season for the Jets."
I'm far from Brett Favre's biggest fan after the choices he's made since the end of the 2007 season. But it would crazy if the organization didn't retire his number some day. And it's reasonable that they want to wait and make sure. Favre says he's done, and he's already contemplating his future career in coaching or broadcasting, but I'd wait too.
Though if there's an undrafted rookie quarterback battling for a roster spot, and attention, he'd sure get a lot of it if he asked to wear number 4.