CLEVELAND, Ohio – Earlier this week I wrote about how Pro Football Focus graded the Browns against the Rams. One story had offensive grades. The other had defensive grades.

One of the grades that really stood out was Nick Chubb’s. He had 23 carries for 96 yards, both season-highs, as well as a 30-yard screen play that set up a touchdown. And yet, his offensive grade was 60.3 against the Rams. His rushing grade was his lowest of the season, 56.4.

This was met with some skepticism by readers because, as my grade stories noted, PFF has explained its grading this way: 100-90 elite; 89-85 Pro Bowler; 84-70 starter; 69-60 backup; 59-0 replaceable.

This led one reader - @brownsfansince79 – to note on Twitter: “It's hard for me to take this too seriously when Nick Chubb graded out as one point above ‘replaceable.’”

How can Chubb be considered a backup- or replaceable-level running back?

It’s worth taking a closer look.

1. Some basic understanding

PFF grades aren’t super complicated to understand, but they’re the best at explaining them, so I’m not going to teach that class here. But I do need to point a couple things.

First, PFF isn’t grading overall talent, just performance on the field. Also, players aren’t graded based on yardage totals and simple counting stats because, as most football fans know by now, stats don’t always tell the whole story.

Second, PFF grades each player on each play, noting that “Even watching a game closely can result in something of a mental highlight reel on a player – remembering the few good and bad plays and making an overall judgment based on the balance of those – but it can be the other 40 snaps in the game that are being ignored that held the true key to his performance.”

2. Chubb’s impressive rookie season

Before we get into Chubb’s value for this season we need to look at last season.

Chubb rushed for 996 yards as a rookie, which was notable because he only got 16 carries over the first six games. And his 5.2 yards per carry average was tied for fourth-best in the league.

PFF thought highly of Chubb last season. His offensive grade (87.4) was first among running backs and the best offensive grade on the Browns. His 90.2 rushing grade was second to the Chargers’ Melvin Gordon III.

But it was more than total yards and yards per carry that earned him that grade.

For example, PFF has an elusive rating, which measures the success and impact of a runner independent of blocking. It’s aimed at seeing how hard he was to bring down and includes missed tackles forced and yards after contact in its formula. Chubb’s elusive rating as a rookie was 103.3, sixth-best.

Browns fans were reminded of that elusiveness on a screen pass against the Titans in Week 1.

Nick Chubb catches a screen from Baker Mayfield against the Titans.

Breakaway percentage measures yardage gained on big plays (15 yards or more). Chubb’s percentage as a rookie was 47.0, which ranked 12th. He had 28 runs of 10 or more yards, seventh-most among running backs.

Where Chubb really excelled last season was in yards after contact. His 4.47-yard average was first among running backs with at least 50 percent of their team’s carries. Even if you take out his 103 yards after contact on three carries against the Raiders, his 4.0 average was still second-best.

3. Chubb through three games

That brings us to this season.

Chubb’s offensive grade is 68.4 (34th) and his rushing grade is 64.5 (46th), far from last season’s marks. His elusive rating is 51.6 (36th), and his breakaway percentage is 21.0 (36th).

Basically, he’s not producing big runs like last year, and he’s also not avoiding tacklers like he did. Both of those facts were displayed on the Browns’ fourth-and-9 draw play against the Rams. Chubb was stopped by Eric Weddle after two yards.

The point here isn’t that Chubb should’ve converted the fourth-and-9 play, but that he was brought down by the first tackler.

“That was on me. I got tackled by one person and I need to find a way to be better and break the tackle, get around him, over him, or something,” he said. “I am taking that one upon myself.”

Nick Chubb is tackled on fourth-and-9 against the Rams.

Chubb’s yards after contact are down to 2.97 (36th) and his yards per carry, 4.0, is tied for 44th. His eight avoided tackles are tied for 12th. Another way of looking at it is he averages an avoided tackle on 13.7 percent of his carries this season. Last season, that percentage was 22.9, and he had the second-most avoided tackles among running backs.

Against the Rams, Chubb’s average yards after contact were 2.83, his lowest of the season, and he avoided just one tackle, according to PFF.

Not all numbers have declined. Chubb has shown improvement as a pass blocker. It has only been 12 pass blocking plays, but his grade (88.2) is second-best among running backs. Last season, he ranked 105th (51.7) and allowed five pressures and had a penalty in 35 pass blocking snaps.

4. PFF isn’t alone in this view of Chubb

Football Outsiders, another analytics website, the founders of that DVOA metric you’ve heard so much about, also take an average view of Chubb.

(DVOA and its relative, DYAR, both measure how far above or below the league average a player is performing. The difference is that DVOA looks at value per play while DYAR is total value of the player.)

Chubb’s DVOA is -9.1 (29th). The negative number means he’s performing below the league average. His DYAR is -1, also ranked 29th.

Football Outsiders notes that an average performance isn’t the worst thing because “an average level of performance is better than that provided by half the league, and the ability to maintain that level of performance while carrying a heavy workload is valuable.”

As for that workload, Chubb’s 58 carries are third-most in the league this season.

A couple other Football Outsider numbers help explain Chubb’s DVOA/DYAR. Success rate measures a player’s consistency when taking into account down and distance (For example, five yards on third-and-4 are more valuable than five yards on third-and-12). Chubb’s success rate this season is 33 percent (39th).

Last season looked like this for Chubb: DVOA 1.1 (24th), DYAR 80 (18th), Success rate 50 percent (19th). Pretty much the epitome of average performance.

Another advanced stat to consider: Next Gen Stats has an efficiency rating that measures the total distance a runner travels per rushing yards gained. The lower the number, the more of a North/South runner the player is. Last season, Chubb was seventh (3.48). This season, he’s tied for 22nd (4.07).

5. What about the offensive line’s role?

Or course, the offensive line impacts Chubb’s performance. Last season he had the second-lowest yards before contact in the league. While the Browns were PFF’s third-ranked pass blocking unit, they were 16th as running blockers.

This season, those numbers have almost reversed. The Browns are seventh in run blocking grades, and 11th in pass blocking. (About that pass blocking grade: PFF gives much of the blame to Baker Mayfield, who is credited with 10 of his own pressures, second-most in the league among quarterbacks.)

As for Football Outsiders, the offensive line isn’t getting its running backs stuffed as much this season (16 percent, ninth) as last (23.1, 29th). Although their power ranking – percentage of short-yardage runs that result in a first down or TD – was low last year (50 percent, 32nd) and is still low this year (33 percent, 28th).

6. So is Chubb a good running back or not?

Last season tells us Chubb has the ability to be among the best in the NFL. But the Browns’ three games this season show that he is not playing up to his rookie level.

The offensive line has improved as a run-blocking unit, but Chubb isn’t breaking long runs, or breaking as many tackles. Yes, 96 yards is still 96 yards. But as we’ve learned, yardage totals don’t mean everything.

This isn’t to say Freddie Kitchens was right or wrong to not use Chubb in the final moments against the Rams on Sunday. It’s also not a call for D’Ernest Johnson or Dontrell Hilliard.

Maybe look at it this way.

You don’t want more Nick Chubb. You want a more efficient Nick Chubb.

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