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Jairus Byrd is one of Buffalo’s most important defensive players and is currently not under contract. The Bills placed a franchise tag on Byrd, but the Pro Bowler has yet to sign the tender or attend optional team workouts. The Bills and Byrd are in contract negotiations regarding a long term deal, but how much is the safety worth? How much should the Bills pay him over how many more years?

This is the first of a five-part determination of how much the Bills should pay Byrd, what they can expect from him in the coming years, how long they should sign him for, how much the team values him, and whether the Bills really need Byrd to become a perennial playoff contender.

In this post, we are going to examine the market rate for safeties. I used AdvancedNFLStats.com’s EPA+ metric over the past three seasons to compare 30 safeties that will be playing the 2013 season outside of their rookie deal. I then compared their EPA+ over the past three seasons to their cap hits over the past two seasons and next season (assuming those seasons “earned” the trailing year’s deal).

I used EPA+ in this study because it measures a player’s positive plays by adding the expected points the opposing offenses failed to gain on plays in which each player was involved. For example, if an offense was facing third and ten fifty yards from the end zone, their expected points (the average points scored by an offense in this situation or later in the series) would be a certain value. A player’s EPA+ would be the offense’s expected points after they forced an incompletion, interception, sack, or whatever minus that prior play’s expected points value.

Basically better players have higher EPA+ totals (in theory). Any metric can be used for this study, but I preferred EPA+ in this situation because it just looks at the results of plays and isn’t subjected to individual stats or an inaccurate weightings of them.

I first compared the maximum EPA+ for the thirty players to their average cap hit from the 2011 to 2013 seasons. The results, along with a polynomial trend line, are in the graph below.


The trend line in this case has a slowly reducing slope as the player’s performance increases, showing a decreasing cap hit for each incremental increase in EPA+. Furthermore, the deviation from the trend line increases as the EPA+ increases. This might be a result of players having breakout seasons or having a great season, getting paid, and then losing productivity.

Based on this data and trend line, Jairus Byrd should be paid $4,639,651, more than $2 million less than the franchise tag salary he is set to make in 2013.

While maximum performances are interesting, they don’t always show how consistent or reliable a player may be. For that reason, I also compared average EPA+ over the past three seasons and the average cap hits from 2011 to 2013. The results are in the graph below.


This trend line is a better fit (R = 0.4544 compared to 0.4217), meaning it explains more of the data points. This trend line also differs from the maximum EPA+ regression because it has an increasing upward slope as EPA+ increases. That makes more sense, since consistently elite safeties are hard to come by and are paid very well for their services.

Based on this regression, Jairus Byrd would be worth roughly $4,800,396 per season. That total is again well below Byrd’s franchise tag salary.

Byrd, however, has been an elite player over the past three seasons. His average EPA+ over the past three seasons would place him as the eleventh best safety in this study. He was the fourth best safety in 2012, according to EPA+. Players with an average EPA+ greater than 35 (twelve total) were paid an average of $136,253 above the salary estimated by the trend line, so there’s hope for Byrd to fetch more than $5 million per season.

Next time, we’ll investigate the aging curve for safeties and determine whether Byrd should be paid more than the trend lines due to the fact that he is coming into his prime rather than declining.