The Bills re-signed RB Johnny White on Tuesday and placed WR David Nelson on injured reserve.
White, a fifth-round pick by the Bills in 2011, was released on Aug. 31. As a rookie last season, White played in 12 games and had 12 carries for 38 yards.
RB Fred Jackson is expected to miss at least three games because of a knee injury, and White will be the team's No. 3 back behind C.J. Spiller and Tashard Choice.
Nelson tore his ACL in Week One.