The Mangenius is headed back to the NFL.
ESPN's Chris Mortensen had the first report.
It's an interesting career choice for Mangini, whose coaching roots trace almost entirely to the defensive side of the ball. According to Rapoport, part of Mangini's role will be to help evaluate how teams plan to defend the 49ers.
He's spent the past two years with ESPN, where he quickly earned a reputation as one of the game's best analysts on television.
Adding some experience as an offensive coach can't hurt Mangini's resume if he has designs on getting back into the big chair. It also puts him in position to move up the Niners' ladder when Roman leaves the nest for a head-coaching job, as many expect he eventually will.
Follow Dan Hanzus on Twitter @DanHanzus.