Thursday, June 18, 2009

Can Brett help Adrian?

One of the persistent reasons I've heard for bringing Brett Favre -- or any quality quarterback -- to the Vikings is that the threat of an improved passing game will open up more holes for Adrian Peterson (and Chester Taylor) to run through, thus improving the running game as well as the passing game. With teams forced to respect the pass more, Peterson will face fewer eight-man fronts and be poised for a spectacular year.

Putting aside the question of whether Brett Favre will improve the Vikings' passing game, I've always found this type of reasoning questionable. Certainly, on the surface, it makes sense, and you hear this logic frequently espoused by commentators and even coaches. But does a better passing game actually improve the running game? And here's another thought: Adrian Peterson has averaged 101.3 yards per game and 5.2 yards per carry during his professional career. Is it really realistic to expect that any improvement to the team will push him much over a 1,600-yard season on a consistent basis?

When you think about it, in terms of raw numbers, an improved passing game should probably decrease overall rushing numbers. After all, if your passing game is good, you should be using it a fair amount, and that's going to take carries away from your running back. The 2008 Vikings threw the ball 452 times (with 43 sacks) and an unknown number of QB scrambles, for about 500 total pass dropbacks. If they'd dropped back to pass 600 times, that would have been 100 or so fewer possibilities for Peterson and Taylor to carry the ball. That'll subtract from your rushing yards, no doubt.

I took a few stabs at this concept last year, and my admittedly amateurish results showed that a good passing game does not help the running game (or vice versa). Brian Burke over at Advanced NFL Stats has talked about a similar topic a few times, and uses what I like to call "The Princess Bride Paradox":

* Your team is very good at rushing. Thus, it should rush the ball.
* The defense knows you're good at rushing. Thus, they'll play a stout run defense.
* You know that the defense knows you're good at rushing. Thus, you'll surprise them by passing!
* The defense knows that you know that they know that you're going to try and stop the run. So you'll outsmart them by playing the pass!
* You know....


Brian's follow-up post used the 2007 Vikings as a specific example by asking what their optimal run-pass mix was, given their talent. His conclusion was that talent on one side of the offense (running or passing) shouldn't affect play-calling on the other side, though he did acknowledge that the passing game improved slightly when Peterson was added in 2007.

But all this still doesn't answer the basic question: Would an improved passing game help Adrian Peterson? Since he ran for 1,760 yards last year at a 4.8 yards-per-carry clip, there doesn't seem to be much that could help him. So I got to wondering, in the best seasons ever by running backs, did those backs have a strong passing game to "open up lanes" for them?

The answer: not so much. I took the top 27 single-season rushing performances -- that's every season of 1,700 or more yards -- and checked out their passing games. Here are the results:

YearRunning BackRush YdsPass AttPass YdsRating
1984Eric Dickerson2,1053582,38265.9
2003Jamal Lewis2,0664152,51764.7
1997Barry Sanders2,0535403,60575.4
1998Terrell Davis2,0084913,80893.5
1973OJ Simpson2,0032131,23642.7
1980Earl Campbell1,9344633,27170.4
1994Barry Sanders1,8834593,08580.2
2003Ahman Green1,8834733,37790.5
2005Shaun Alexander1,8804743,63296.8
1963Jim Brown1,8633222,44978.3
2005Tiki Barber1,8605583,76275.7
2002Ricky Williams1,8534553,06979.3
1977Walter Payton1,8523052,07061.8
1998Jamal Anderson1,8464243,74492.7
1986Eric Dickerson1,8214032,38063.7
1975OJ Simpson1,8173542,66180.2
2006LaDainian Tomlinson1,8154663,41293.0
1983Eric Dickerson1,8084893,41176.0
2006Larry Johnson1,7894503,24384.7
1995Emmitt Smith1,7734943,74191.7
2008Adrian Peterson1,7604523,21781.5
1985Marcus Allen1,7595063,48168.5
1997Terrell Davis1,7505133,70487.4
2005Larry Johnson1,7505074,01490.1
1985Gerald Riggs1,7194623,02566.5
1992Emmitt Smith1,7134913,59788.8
2000Edgerrin James1,7095714,41394.7


The five running backs with 2,000-yard seasons had Jeff Kemp, Kyle Boller, Scott Mitchell, John Elway, and Joe Ferguson as their primary quarterbacks. Apart from Elway (who missed four games with injury and was replaced by Bubby Brister), that's a pretty sorry group.

Only eight of the 27 seasons featured quarterbacks with passer ratings of 90 or higher and the overall weighted average is 80.5 and the better entries seem to be clumped down near the bottom, with the lower rushing totals. That's not real impressive, and only four of these 27 seasons occurred before the changes to open up the passing game in 1979.

Of course, what I should really be looking at is overall rushing totals for an entire team (minus quarterback rushing numbers), but that would require more effort than I'm willing to put in :P Still, consider the following additional two seasons:

YearRunning BackRush YdsPass AttPass YdsRating
2007C. P.
2008C. P.


Those are a couple more excellent 1700+ yard seasons that would be added to the list above if "C. P." were a real person. He's actually the combined rushing numbers of Adrian Peterson and Chester Taylor ("Chester Peterson"), multiplied by 80% to give a reasonable number of carries (316 and 372 for 2007 and 2008, respectively) and represent that C. P. probably wouldn't be actually able to carry the ball 859 times over consecutive seasons. Again, the quarterbacking for C. P.'s team has been mediocre to poor for two seasons, yet he's put up spectacular numbers. How would adding a better quarterback improve them?

Without question, better quarterback play would improve the Minnesota Vikings as a team, though whether it would improve the running game is, I think, questionable. Even if we could somehow acquire the in-their-prime versions of Joe Montana and Jerry Rice and plant them on the '09 Vikings, Adrian Peterson would be hard-pressed to improve on his stats from the previous two years. There are just only so many plays to go around, and if the passing game is that much more improved, we should use it more.

Pacifist Viking does raise a good point, though. It might be that an improved passing game will make Peterson more consistent on a per-play basis. I brought up Barry Sanders in the discussion, as a perfect example of a player who very rarely had a good passing game to support him and could be maddeningly inconsistent on a carry-by-carry basis. Without access to play-by-play data, it'll be tough to prove/disprove this, but it's a decent enough assumption. Personally, I think consistency is overrated, but that's a topic for another post.

Based on the evidence from NFL history, though, it's hard for me to believe that an outstanding rushing season is the result of good passing from the same team. Some of this might be because, with limited resources (i.e., cap room), teams can't invest in as much. So you have a great running back and so-so QB and receivers (and a line that's better at run blocking than pass protection); all that might result in some of the disparity we see here. But when it comes to improving your running game, the most important factor, I feel, is the talent of your running back and his blockers -- not your quarterback and receivers.


Peter said...

Good points, nice logic. I like your analysis.

An improved passing game (or a QB who instills more fear in opposing defenses, at least) typically hurts total rushing yardage because, like you pointed out, there are fewer carries. Conversely, it should help the runners' YardsPerCarry stat as fewer defenders are focused on them.

With Adrian Peterson, however, you have an atypical back. His carries and yardage currently tend to look something like this:


That's 11 caries for 77 yards, or 7 yards per carry. (let's call that 2 quarters of play) With Favre at QB, let's say Peterson only gets 8 carries. This would reduce the total yardage for most backs, but I could see something like this happening:


There's 8 carries for 116 yards at 14.5 yards per carry. YPC is up (as expected) but total yardage is also up despite fewer carries (which shouldn't happen for most runningbacks). Here's why I see that happening:

Peterson currently tries to make something out of nothing (8-9 in the box), and succeeds often enough that he's a successful runner. His averages look nice, but as PV pointed out, his consistency is bad (very high standard deviation). A better passing game means fewer carries, but it also means that each of those carries has more opportunity than before. If his carries get reduced from 11 to 8, the opportunity per carry goes up by a ratio greater than 11:8 and he'll get more overall yardage as a result.

The obvious argument against this is that he might hit fewer homeruns with more defenders playing the pass; they'll be the ones to tackle him after he gets past the first line of defense. I think he'll have a few would-be long touchdown runs foiled halfway because a nickleback pushes him toward a safety or a corner, but for the most part, Peterson is quick and elusive enough to avoid being tackled in the open field (think Kenoy Kennedy).

Dang, I should have a blog.

Jason said...

That's exactly the same kind of reasoning I used on my other posts that I linked to -- better passing game = lower total rushing yards but higher yards per rush.

Unfortunately, my results were inconclusive, to the point that I didn't believe there was an actual correlation between the two. Maybe I'll run the 2008 numbers this time.

Peter said...

and you did? (I see another post!) awesome. I'm going to go read it.

Shawn said...

Better total yards? Of course not. No one is arguing that. I expect to see better yards per carry & fewer carries which helps AP avoid injury and keeps him fresh for the playoffs. I also expect to see him catch a few more swing/screen passes.

Jason said...

Better total yards? Of course not. No one is arguing that.

Yes, they are.

"Does value go that much higher if/when Favre joins the team? Do we see a 2,000 yard season in him?"

"If Favre goes, I think that Peterson will hit 2,000 rushing yards."

"This could well be the missing piece...I fully expect Peterson to rush for 2,000 yards this season." (comment by patsSB44champs)

"Adding Favre might make a 2,000-yard season possible."

"Expect him to come close to 2,000 yards rushing this year, especially if Brett Favre joins the Vikings."

"With already a stalwart defense and punishing offensive line, an upper echelon veteran quarterback would have made Minnesota arguably the leading contender in the NFC. Adrian Peterson would have seen fewer eight-and nine-man fronts, all but ensuring a 2,000-yard season for the game’s best running back."

And that's only after three pages of this search.