The Minnesota Vikings will sign free agent guard Alex Boone, reports Adam Scefter of ESPN.
The 29-year-old leaves San Francisco after seven seasons with the franchise, including a year spent on the practice squad. Boone developed into one of the mainstays of a solid offensive line, playing both right and left guard.
Boone has started 59 of 60 games played over the last four seasons. He was originally signed by the 49ers as an undrafted free agent out of Ohio State in 2009.
He had an at-times tumultuous tenure with the 49ers, twice holding out and both defending and criticizing former coach Jim Harbaugh.
The terms of the deal with Minnesota are not yet known.