Been at Winter Park the last two days, and head coach Mike Zimmer and offensive coordinator Norv Turner have both taken shots at Pro Football Focus' preseason individual grades.

Their message: Someone watching film who doesn't know what the players' assignments were on every play can't know how well they performed.

My takes on this:

-These guys have every right to tell us when we are, or PFF is, wrong. We also have the the right to be dubious about NFL coaches offering accurate assessments of their own players, because they so rarely do.

-Our job in the media is to use stats, whether old-school versions or advanced metrics, to illuminate subjects. But it's also our job to add the context that can make a statistic worthwhile. You have to use a combination of data, sourcing and first-person observation to complete the picture.

This is why good beat writers are so valuable. They're capable of filling in the blanks when a player has an apparently poor performance. Maybe the guy next to him missed an assignment. Maybe he's playing with a bad foot. And, yes, maybe he just played lousy.

I think Pro Football Focus does a masterful job of evaluating film, but I wouldn't take their grades as gospel, just as I wouldn't take anything an NFL coach says in public as gospel.

When I was covering the Vikings in 1999, I watched the tape of a game and downgraded the offensive line. I showed up at the facility the next day ,and Mike Tice, then the offensive line coach, called me in and showed me where I was wrong. Since then, I've been very cautious about grading out offensive line play. It really is a mystery to just about everyone who isn't in the team's offensive meeting rooms.

Over time, you get a good sense of how well a player performs - it didn't require much studying to judge Randall McDaniel as one of the best football players who ever lived - but picking apart one play or one game is risky.

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I'll be on 1500ESPN at an unusual time tomorrow - 11:15 a.m.

We'll run Sunday Sports Talk from the fair, Sunday 10-noon.