Winning a job in the NFL is the easy part. Anyone will tell you that keeping it is far more difficult. Most players are lucky to keep a roster spot for two or three years before a team decides to move on. The Chicago Bears have repeatedly proven this with their mass roster turnovers during the previous decade. As GM Ryan Poles and head coach Matt Eberflus continue to haul in more young talent, it has put several notable veterans on notice. This training camp may be the most consequential of their professional careers.