Pro Football Focus is a wonderful website that has a lot of great information. I do have some problems with the site, however. A lot of people don't realize that they pump out two different types of numbers. They have some advanced statistics. They can tell you things like how many yards a back gained after contact or what a quarterback's completion percentage was when he was under pressure. This is really useful information that goes deeper than traditional stats.
PFF also has player grades where they say they grade players on the field. They have never been good at explaining how their system works. It is not a transparent system, and there are significant questions about the validity of the grades. They gave Aaron Rodgers a negative grade in a game this past season where he threw 5 touchdown passes against the Chiefs. This was an extreme case, but there are plenty of cases where their grades in a given game don't make a whole lot of sense.
PFF's grades now rank players on a scale from 1 to 100. Yesterday they released a tracker of free agents to be. Just looking at the free agents the Jets have leads to some real head scratchers.
|Player||Grade||Position||Age||Team||Snaps||Free Agent Type|
Now just the top two are puzzling. Damon Harrison gets a higher grade by their methodology than Muhammad Wilkerson. Some people may argue the Jets should keep Harrison over Wilkerson, but they are making a value argument. Harrison will cost less so the Jets can still get a high quality defensive line and have extra money to spend elsewhere.
I don't think anybody is stating the case that Harrison is actually a better player, though. That argument doesn't make a whole lot of sense. Harrison is a premium run defender, but Wilkerson is also very good against the run. When it comes to the pass rush, though, Harrison is a nonentity. He had 0.5 sacks this season. Wilkerson had 12. It's very difficult to argue the gap between Harrison and Wilkerson as run defenders is greater than the gap between Wilkerson and Harrison as pass rushers. And as for value, Harrison played in almost 400 less snaps.
That's nothing compared with the ratings they have for Ryan Fitzpatrick, though. I know Fitzpatrick is polarizing. I know he's a regression candidate. I know he benefited from good receivers. Should his grade really be lower than Stevan Ridley's though? How about Darrin Walls? Ryan Quigley? Antonio Allen and Zach Sudfeld didn't even play this season, and they're graded higher. So bad backups, a bad punter, and two guys who spend the year on IR are worth a higher grade than a quarterback who threw for 31 touchdowns against 15 interceptions?
None of this makes sense, and PFF refuses to explain its grading system beyond vague generalities.
I'll use PFF's stats (rushing yards after contact, completion percentage under pressure), but I sparingly use these grades. This is a good example of why.