Let me first point out that Richard Sherman was Pro Football Focus' highest-graded (90.3) cornerback last season. The San Francisco 49ers veteran defender is one of just two cornerbacks who have been targeted more than 250 times over the past decade and allowed a completion rate of less than 50 percent. The other is Darrelle Revis.
Sherman is pretty good, and the analytics back that up.
During an Instagram interview with Pro Football Focus, however, Sherman didn't sound ready to endorse the analytics site's grading system. Let's be clear; the cornerback will often share social media posts from Pro Football Focus that tout the high level of play from fellow defenders—especially the defensive backs.
Despite being named among the league's best last season by the analytics site, Sherman pointed out why he felt the grading process, at least at times, could be flawed.
"I'll go games where I don't get targeted the whole game, and in your system, it's kind of like a flat grade for that," Sherman explained during the lengthy conversation. "There's no way to quantify that. But in terms of what we're doing schematically, and how I'm judged off doing my job and making tackles, and being sound, I'm usually right on it.
"And then I'll look up at the grade I'm getting from PFF, and it will be like, 'Well, we didn't have enough information. You didn't get targeted, so there's no way to give you a great grade.' Then it's like, what am I supposed to do? If I get targeted 10 times, and I can get a bunch of PBUs, I can get a high grade. But if I don't get targeted at all, [I can't]."
The interviewer noted that Pro Football Focus is working on finding ways to credit defensive backs who aren't targeted in games. He even invited Sherman to come work for the analytics site and help improve its grading system once his playing days are over.
As noted above, Sherman shares Pro Football Focus' posts, so he does find value in it. Is it perfect? No. No grading system is, especially when you don't have inside knowledge from coaches of what they expect from each player on every play.
Pro Football Focus' data is a tool. One of many that can be used in conjunction with others for player evaluation.
"I think you guys are doing a great job because it's so new," Sherman continued. "So obviously, it will evolve over time. You guys will get better. But there are so many variables involved in coverage, and especially when you're not grading it with an understanding of the scheme that they're running."
Sherman believes analytics can be improved by blending the data with input from those who had a much better understanding of what each team is trying to accomplish with every play.
"I think that you guys' system just needs more conversation," Sherman shared. "More conversation with maybe coordinators and players, I guess. Because the coordinator would be able to coach you up and say, 'Hey, this is what they're responsible for. This is how important it was to the defense.' ... There's too many variables."