As with any NFL team, turnover of personnel or coaching staff can cause problems with continuity. If you look at the good defensive teams this year (ESPN.com-total defense statistics), each of them had low turnover on defense the year before. Teams like 49ers (all 11 returned), Cowboys, Lions (lost Eric Wright to Bucs, Berry released for discipline) Texans (traded MLB DeMeco Ryans-to Eagles, lost Mario Williams to free agency -Bills), and Steelers.

The Lions have a problem with contracts expiring in 2013. Here are the list of Lion's players that are unrestricted free agents (UFA) and restricted free agents (RFA)

Offense

UFA's

Gosder Cherilus-OT Starter

Dylan Gandy- G/C

Jason Hanson-K

Stefan Logan-RB/WR/RET

Kevin Smith- RB

Corey Hilliard-OT

Will Heller- TE

RFA's

Joique Bell-RB

Jason Fox-OT

Keiland Williams- RB

Defense

UFA's

Cliff Avril- DE Starter

Louis Delmas-S Starter

Justin Durant- LB Starter

Sammie Lee Hill-DT Key Rotational

Chris Houston-CB Starter

Lawrence Jackson- DE Key Rotational

Jacob Lacey-CB Nickel

DeAndre Levy-LB Starter

Ashlee Palmer- LB back-up

Corey Williams- DT Starter

Eric Coleman- S Starter

RFA's

Willie Young- DE Key Rotational

Amari Spievey- S

Ricardo Silva-S

This list only compiles the players that are UFA's and RFA's for 2013, it doesn't include the players that are going to be in the last year of their contracts (Jeff Backus, Stephen Peterman, Shaun Hill, Dominic Raiola, Tony Scheffler, Kyle Vanden Bosch, and John Wendling). If Cherilus leaves this year, and Peterman, Backus, and Raiola go the following, that would be 4/5 of our offensive line leaving over the next two years. It will be hard for our offense if we have to replace nearly our entire offensive line in a matter of 2 years. I like that the Lions are trying to insulate the line with players that could take over next year. Reiff, Nagy, and Fox could be solutions to the problem, but only time will tell.

Our biggest problem is that our defense is looking at 6 defensive starters going to be free agents not to mention two rotational d-linemen.

Now, not all these players will be sought after in free agency, but we still need to keep the youthful vets that are the foundation of this franchise; players like Willie Young, Sammie Lee Hill, Louis Delmas, Amari Spievey (probably would get through waivers), DeAndre Levy, and Ricardo Silva. Justin Durant is a tough call, he has played pretty well in that Levy, Tulloch, Durant linebacker trio, but of the 3 he could be the most expendable, especially if Doug Hogue or Travis Lewis step up in OTA's and training camp.

This post isn't about who we should keep and cut, but we need to be aware that our defense could look dramatically different from this year. The Lions did a good job at adding talent to the defense with the 2012 NFL Draft (Bentley, R. Lewis, T. Lewis, T. Whitehead, Chris Greenwood, and Jonte Green). We could see changes in all three levels, if we cannot get deals done with some of these key players, and allow our rookies to grow another year or two. All we know is that Mayhew should be looking at our current contracts and get our players locked up for the next few years. With this problem solved we can start making moves that will put us in the driver's seat for next season.

Sources:

http://www.rotoworld.com/teams/contracts/nfl/det/

http://espn.go.com/nfl/statistics/team/_/stat/total/position/defense