Coach Mike Zimmer said Wednesday that Mauti needed minor surgery on his knee. The second-year player from Penn State has played almost exclusively on special teams.
Bykowski had been on the practice squad with the 49ers since they drafted him in the seventh round before the 2013 season. He's from Eden Prairie, where the Vikings have their suburban headquarters, and played in high school for coach Mike Grant, the son of former Vikings coach and Pro Football Hall of Fame member Bud Grant.
Bykowski played at Iowa State, where he switched from tight end to tackle.