This defensive challenge could expose everything for the Patriots

New England Patriots linebacker Robert Spillane | Icon Sportswire/GettyImagesThe New England Patriots lost one of their best and most important defensive players to foot and ankle injuries that kept him from playing a snap against the Buffalo Bills last week. Robert Spillane has been the team's leading tackler, racking up 97 in total to this point. PFF grades him to be the league's 13th-best linebacker and among the most effective against the run, with an 87.3 overall grade.

His absence against Buffalo was felt. The middle of the field seemed wide open, with James Cook becoming the second player this season to amass over 100 rushing yards against the Patriots. Tight ends have also hurt New…