Browns make switch at safety against Bills
Young, who started eight games last season, has yet to play a defensive snap this season.
Hagg started Cleveland's first two games. He gave up a 44-yard TD pass in the 34-27 loss to the Bengals.
Browns tight end Alex Smith was also inactive Sunday. He sustained a concussion last week and was briefly hospitalized.
There were no major lineup changes for the Bills. As expected, running back C.J. Spiller will start for Fred Jackson, sidelined with a sprained knee. Spiller enters the game as the NFL's leading rusher, averaging 10.1 yards per carry.