Who’s the best cornerback in the NFL?
Some fans think New York Jets star Darrelle Revis, while others say it’s Oakland Raiders veteran Nnamdi Asomugha. It is an argument that simply cannot be won.
The Revis side will throw out his 23 passes defensed and how quarterbacks completed just 36.9 percent of their passes towards Revis last season.
Asomugha supporters will point out that only 28 passes came his way all of last season, so one can contend that he did his job better since no one is throwing at him.
So, is there a way to come up with a ranking system that would avoid as much bias and subjectivity as possible?
Stats with the least amount of subjectivity for cornerbacks are snaps, TA, Receptions Against, Catch Percentage, Interceptions, and Pass Deflections.
The challenge is to figure out a way to compare players that did not have equal opportunities. There is a yards per carry average for running backs that does just that, but for cornerbacks there is no such statistic.
My ranking is ultimately composed of three distinct parts.
Part 1: Playmaking (PM) – ((PD+INT)/TA)
This number provides a way to compare Player A, thrown at 100 times with 6 INT and 10 PD, to Player B, thrown at 50 times with 4 INT and 6 PD. Obviously the second player was better.
Weighted PM: (PM*TA%): This weights the PM based on the number of opportunities each player had to make a play.
Stat goals: Compensate for the number of opportunities the defense had and provide weight to what the player did when thrown at.
Part 2: Catch Percentage (61%-Catch%)*TA%
Catch percentage weighted based upon a 61% average NFL QB completion percentage. Allowing 62% completions would be -1% and allowing 55% would be +6% over average.
Take this result and add weight depending on the TA% for each player.
Stat goals: Weight the typical catch percentage based upon thrown at and compare to the average completion percentage of an NFL quarterback to determine a rating over or under average catch percentage.
Part 3: Good Coverage (Expressed as NT%)
In this case, how often was the player NOT thrown at on a passing play. Using snaps and TA to create a percentage.
This is the total percentage of passing play snaps where the player was not thrown at. Good coverage is assumed in this case.
Stat goals: This can’t directly measure good coverage, because there are a variety of factors that could prevent a corner from being thrown at. What it does do, is provide a non-subjective measurement of the corners coverage ability within his defensive scheme and situation. You can’t cheat this stat.
I know all the Raiders fans wanted to see this: Nnamdi Asomugha ranked first. Darrelle Revis second. Charles Woodson third.
I will point out these rankings are based purely on coverage, since coverage is the corner’s primary responsibility.
Revis was thrown at a disproportionate amount of times for how productive he was in 2009. Expect Revis to receive the Asomugha treatment in 2010. Limiting Revis’ opportunities to make plays will likely suppress his INT and PD numbers and elevate his the percentage of passes caught against him.
This is a win for the Jets defense if the number two corner is also productive.
To Revis’ credit, he ranked first in Weighted PM and Weighted Catch Percentage. Revis’ high TA% suppressed his numbers slightly.
If Revis maintains his weighted PM and Weighted Catch Precentage and ultimately sees fewer passes and receptions to his side of the field in 2010, he could conceivably pass Asomugha.
Where did Chris Johnson rank? 61st out of 65 players who played 50% of snaps.
Johnson was thrown at an amazing 21.2% of the pass plays he was on the field. That is the highest in the league. If there is a silver lining, it is that Johnson ranked sixth in weighted Playmaking.
Nick Harper was the worst overall. You can see the full ranking below.
*Snaps, TA, Rec Against, Catch %, INT, and PD stats provided by profootballfocus.com