Zimmer says media, fans should take Pro Football Focus grades 'with a grain of salt'

Before Mike Zimmer fielded questions from reporters today, he made a few announcements.

One was that he had picked a QB. We knew that was coming. Another was that a bunch of players were released. We figured that one would be coming, too. But the last announcement Zimmer made came out of nowhere, and it was about one of the most popular NFL analytics sites on the web.

Zimmer aired out his reservations about Pro Football Focus, a website whose data we sometimes use on this blog. While he was polite about it, the Vikings head coach made it clear he has concerns about their individual grades for players, which are done by a grader watching the coaches film.

"I look at the grades and I can't tell you what a 0.7 is or anything like that," said Zimmer, who is in his first year as head coach. "I know the people that are grading our games and our defenses and our offenses, they don't know if the tackle gets beat inside he wasn't sliding out to the nickel, or who our guys are supposed to cover. I guarantee they don't know who's in our blitz package and what they're supposed to do. I would just ask that everybody take that with a grain of salt, including our fans. We as coaches get paid a whole bunch of money to do the jobs that we do, evaluate the players that we evaluate and grade them how we grade them, not based on something else."

For a full explanation from Pro Football Focus on how and why they do their grades, click right here.

We occasionally reference their grades on this blog, but we try to be careful about it for the same reason Zimmer stated. In some cases, it's obvious when a defensive end makes a great play or a receiver drops a pass he shouldn't have. In other cases, the evaluations get a little murky.

That being said, PFF is a great resource for advanced stats on things like a wide receiver's catch rate, which linemen the backs run behind most and which pass rushers disrupt quarterbacks most.

Peter King of MMQB wrote today that 13 teams currently have contracts with Pro Football Focus.

The NFL has certainly embraced the use of analytics in chorus with their own scouting and player evaluation, with some teams embracing it firmer than others. Sure, there are plenty of old-school coaches and scouts — I'm not saying Zimmer is one of them — who may always be skeptical of what someone with a calculator tells them opposed to seeing it with their own two eyes. But teams such as the Ravens, Jaguars, Browns, Rams and Bills have dipped their toes into the analytical waters.

The Jaguars even said one PFF study helped convince them to draft tackle Luke Joeckel in 2013.

But when it comes to grading players, Zimmer made it clear that the Vikings will stick with their own grades, though something tells me they won't be publishing them to the internet like PFF does.