One needs to look no further than Buffalo Bills ' defensive coordinator Jim Leonhard to see what's possible for an undrafted rookie in the NFL. In 2005, Leonhard made Buffalo's 53-man roster after going undrafted out of Wisconsin. The high-motor safety went on to play 10 seasons in the league before transitioning to coaching. As for current Bills' players, offensive lineman Alec Anderson, linebacker Joe Andreessen and wide receiver Tyrell Shavers all signed undrafted free agent contracts out of college. Sep 15, 2013; Orchard Park, NY, USA; Buffalo Bills defensive back Jim Leonhard (35) during a game against the Carolina Panthers at Ralph Wilson Stadium. | Timothy T. Ludwig-Imagn Images This week, Buffalo announced the addition of 12 undrafted rookies with some naturally holding better survival odds than others.…