The Bills signed draft picks Ko Simpson, Kyle Williams, Brad Butler and Aaron Merz on Monday. Simpson, a fourth-round selection out of South Carolina, led the Gamecocks in tackles in 2005 with 103. Williams, a fifth-round pick, was a three-year starting defensive tackle with LSU. Butler, also taken in the fifth round, played offensive tackle for Virginia last season. Merz, Buffalo's final draft pick in the seventh round, went from a walk-on to a starter on the offensive line at California, starting 27 games during his four-year career.