Change is inherent in the very fabric of the NFL. From year to year, little stays the same for most teams. But the team that changed the least from 2013 to 2014 was … the Dallas Cowboys?

There were six Dallas players who produced 12 or more points of Approximate Value last year: DeMarco Murray, Tony Romo, Tyron Smith, Dez Bryant, Zack Martin, and Travis Frederick. Of that group, all but Martin were key contributors in 2013, too. As measured by AV, the only big changes for the Cowboys were the losses of Jason Hatcher (8 points of AV in 2013), DeMarcus Ware (5) and Sean Lee (5). And other than Martin, the only notable players for the team last year that weren’t key parts of the team in 2013 were DE Jeremy Mincey, FS J.J. Wilcox, OLB Anthony Hitchens, ILB Rolando McClain, and DE Tyrone Crawford. And, perhaps, another reason the Cowboys may have appeared to have little turnover last year? Dallas generally stayed very healthy, which is one way of keeping the same players in the lineup year over year.

Meanwhile, the team with the biggest turnover in 2014? The Oakland Raiders. That’s not much of a surprise, so let’s instead look at the team with the 4th largest turnover, which happens to be the team with the most turnover that made the playoffs: the Arizona Cardinals. CB Antonio Cromartie, ILB Larry Foote, DE Tommy Kelly, and S Deone Bucannon were starters in 2014 but weren’t on the team in 2013; OLB Alex Okafor played in 1 games in 2013 and started 12 games last year; and safeties Rashad Johnson and Tony Jefferson started, collectively, 15 more games in 2014 than they did the prior year.

Meanwhile, the left side of the offensive line was rebuilt by adding Jared Veldheer (Oakland) and Ted Larsen (Tampa Bay). The 2014 Cardinals were successful despite losing the player with the most AV of anyone on the team in 2013: Karlos Dansby, who signed with Cleveland in the offseason. The Cardinals also saw almost no contribution from OLB John Abraham or DE Darnell Dockett, while losing ILB Daryl Washington for the year to suspension: those three were key contributors to the front seven two years ago.

I calculated the amount of turnover each team had from 2013 to 2014 using the following methodology:

1) Calculate the percentage of team AV gained by each player in 2014.

2) Calculate the percentage of team AV gained by that player for that team in 2013.

3) Take the lower of those two values.

4) Sum the values of each player for each team to derive a team retention grade for each franchise.

Using this methodology, 69.5% of the Cowboys value was retained from 2013 to 2014, compared to just 43.1% of Arizona’s value.  In the graph below, I’ve plotted each of the 32 teams, with their AV retention rate on the Y-Axis and winning percentage in 2014 on the X-Axis.  Arizona is a bit of an outlier by being in the bottom right, while Dallas and many of the best teams from last year are in the upper right corner of the graph.

I’m a bit short on time today, so I’ll leave the commentary to you guys.  I have presented the same information below in table form, and also included 2013 win percentage and the difference between team winning percentage in 2013 and 2014 for each franchise.  Let me know what you discover!