Turnovers are great for a defense. Turnover - in personnel, and on the coaching staff - is not. The 2014 offseason will mark the fourth straight year Buffalo Bills defenders will be working for a new defensive coordinator, following yesterday's departure of Mike Pettine. A sizable chunk of the Bills defense has never played consecutive seasons under the same coordinator while in Buffalo.

In 2013, Pettine led a much improved unit following the ouster of Dave Wannstedt and the rest of the Bills coaching staff following the 2012 season. Wannstedt had replaced George Edwards - the new Minnesota Vikings defensive coordinator, if you hadn't heard - who had the Bills ranked No. 30 in scoring defense in 2011. Edwards is the last man to hold the job for consecutive seasons (2010-11). Prior to that, Perry Fewell served four seasons in the post.

Buffalo's 2011 NFL Draft class, in particular, will enter their fourth seasons as pros with a fourth new coordinator. Marcell Dareus, Aaron Williams and Da'Norris Searcy were all featured players in Pettine's defense - Williams, in particular, seemed to have finally found his footing in Pettine's system - and face the unpleasant truth of playing for a fourth coordinator in as many years next season. Similarly, 2012 draft picks Stephon Gilmore and Nigel Bradham will have never played for the same coordinator twice, and obviously the same applies to 2013 rookies Kiko Alonso and Nickell Robey.

On the free agent front, Mario Williams will be on his fourth defensive coordinator in four years going back to his time with the Houston Texans, presuming Wade Phillips doesn't get hired to replace Pettine. Williams is the sixth prominent Bills defender that has spent multiple seasons in Buffalo without the same coordinator in consecutive seasons (a number that excludes Alonso, Robey, and 2013 additions Alan Branch, Manny Lawson and Jerry Hughes).