Down to just one healthy quarterback, and with injured starter J.P. Losman expected to miss at least two weeks with a sprained left knee, the Buffalo Bills on Monday re-signed veteran free agent Craig Nall, who the team had released at the end of the preseason. Nall, 28, will serve as the backup to rookie Trent Edwards, who replaced Losman in the first quarter of Sunday's 38-7 loss to New England, and who will make his first regular-season start next Sunday when the Bills host the New York Jets.