Why is this guy in the conversation?
There's an ongoing debate in the NFL right now. 4 guys are involved in this dispute, all have been or will be paid in the near future. Richard Sherman, Patrick Peterson, Joe Haden, and Darrell Revis are the four best cornerbacks in the NFL today. They have shut down some of the best receiver-QB connections in the game, taken away entire areas of the field, and given the ball back to their offense with quite a bit of regularity. The crazy thing is, only two of them have the measurable attributes that you would expect a corner to have, the speed and agility that you would "need" to shut down the best receivers in the game, and one of them still needs work doing that.
First I need to get something off my chest. Patrick Peterson should not be on this list or in this argument. He has games where he can take over against receivers, and he also has games where his footwork gets out of whack and he can be out muscled fairly easily by bigger receivers. So in other words, he's inconsistent. Very, very inconsistent. In my mind he's got all the potential in the world, and he's only 23, so he's got time to refine this technique, but he's not in the conversation at this point in time. He does follow receivers around, but you'd see plays like this:
He IS a good player, and he also returns kicks and punts, which does add some value to him as a player, but he's not on the same level as some of those other players. He allows more TDs and doesn't pick up as many INTs as the elite players. I respect his game, and he's got a lot of potential, but potential doesn't matter on the field. You don't get to allow a passer rating of more than 90 and be called a shut down corner.
With that out of the way you get down to three guys. Revis, Sherman, and Haden. Let's get this one hammered out, shall we?
Looking at the stats over their careers, Sherman takes a clear lead over Haden, with more INTs, only 8 fewer passes defensed after playing in 9 fewer games, more forced fumbles, and has more defensive TDs. Those are just the stats that are recorded online in basic sites, and if you look at more advanced stats (I only have access to a few of them, I don't pay for PFF), Sherman has also had a lower passer rating allowed, a higher coverage grade, and has allowed fewer TDs than Haden in any year that he's been in the league.
In the article I read on the three younger corners (this one), there's a bonus in the comments, our old friend Arif Hasan makes an appearance! He's on Sherman's side in this case. He points out that despite the fact that Sherman didn't follow receivers around the field, he did face #1 receivers more than 1/4 of the time, and Peterson didn't follow #1 receivers constantly either. Haden did see those receivers 65% of the time, but that's only a difference of 28%. And since the passer rating difference between #1 and #2 receivers is about 12 points, that should be good for about a difference of 4 points. That's not quite as big a difference as the 27 point difference that actually existed.
So, having established that Haden is below Sherman, we get to the harder part. I don't have access to some of the advanced stats out there on Darrelle Revis, so I have to take a more roundabout route to find some of these.
First off, Sherman creates many more turnovers, Revis actually only has one more career interception, despite playing almost twice as many games as Sherman. Revis actually has fewer forced fumbles, and has consistently allowed a higher passer rating and completion percentage than Sherman has.
Revis was ranked higher in terms of a pure cornerback grade, but PFF ultimately granted a higher place on their top 101 players to Sherman (Revis was 18th to Sherman's 6th). Whether or not the Buccaneers misused Revis is still in question, but he does have a history of taking the opponent's #1 guy away. Compare that with Sherman, who can take away a side of the field with regularity. There is a massive difference in scheme, and when you look at what Sherman is asked to to, it's not as much as what Revis does. But that's not the issue. When you play in a certain scheme you can't break that scheme just to solidify an argument about who's best. Neither of these guys do.
In the end who's the "best" is a matter of opinion. There will never be any real consensus in this matter. What I can say is that whenever there's been a debate recently about the best cornerback in the league there's one constant presence in that debate. Sherman, no matter what the analysts said in the last debate about cornerbacks, is ALWAYS a part of the discussion.
The crux of the matter (title drop!) is that regardless of scheme a cornerback's job is to face a receiver, stop the ball from being caught, or to catch it yourself. In this league right now there's not one person who does that job better than Richard Kevin Sherman of the World Champion Seattle Seahawks.
By the way, if you want more and better analysis of why Sherman is awesome, go check out Danny's article here. It's much better than this one.