So the headline is slightly deceiving. You could actually point to a number of different stats that help explain why the Cubs have had such a great year: ERA (3.44), OBP (.320), and record in one-run games (33-21) to name a few. However, I think there’s one under-the-radar stat that better explains the Cubs offensive success better than any other. Plus you wouldn’t have read this post if the headline read “One of Many Stats That Explains the Cubs’ Success.”
So, what’s the stat? Pitches Per Plate Appearance.
Entering play on September 30, Cubs’ batters have seen an average of 3.97 pitches per plate appearance in 2015. That may not sound like many, but it’s the highest number of any team in Major League Baseball.
Theo Shares the Secret
I was originally intrigued by the importance of “Pitches Per Plate Appearance” when I read an excellent feature article that Joe Posnanski wrote on Cubs’ President of Baseball Operations, Theo Epstein, in early September. In the piece, when talking about the Cubs’ newfound success this year Epstein said the following: “Not that it’s a perfect measuring stick by any means, but if you look at our pitches per plate appearance, we were 30th and we increased it a little bit each year. Now we lead the league in pitches per plate appearances. Our walks and our on-base percentage have followed suit – it’s the same in the minor leagues. We have a ton of guys who know how to grind out at-bats.”
Chicago Tribune
Why Pitches Per Plate Appearance?
According to Epstein, Pitches Per Plate Appearance is important to the Cubs. It’s something they value. But why? What makes the stat useful?
To answer that question, I think it’s helpful to begin by looking back at a quote from baseball writer/mathematician Bill James. In his 1985 Historical Baseball Abstract, James wrote about the “key question” when evaluating a player’s offensive performance:
With regard to an offensive player, the first key question is how many runs have resulted from what he has done with the bat and on the basepaths. Willie McCovey hit .270 in his career, with 353 doubles, 46 triples, 521 home runs and 1,345 walks -- but his job was not to hit doubles, nor to hit singles, nor to hit triples, nor to draw walks or even hit home runs, but rather to put runs on the scoreboard.
So, if we’re on the same wavelength as James, we have to look at each offensive stat with “runs-colored glasses.” That is, each offensive stat is only ultimately useful if it can help explain runs scored. With that in mind, let’s take a look at the Cubs offense over the last four seasons.
| Year | Pitches/PA | Runs |
|---|---|---|
| 2015 | 3.974 | 664 |
| 2014 | 3.888 | 614 |
| 2013 | 3.857 | 602 |
| 2012 | 3.786 | 613 |
As Epstein mentioned, the Cubs have improved in Pitches Per Plate Appearance each year. And, other than a slight blip in 2013 (which can be explained by a unusually low BABIP), the Cubs have scored more runs each year.
Beyond the Cubs, let’s take a look at the rest of the National League this year.
| Team | Pitches/PA | WAR |
|---|---|---|
| Cubs | 3.974496 | 23.6 |
| Mets | 3.882943 | 23.4 |
| Dodgers | 3.877258 | 25.8 |
| Padres | 3.850915 | 13.7 |
| Cardinals | 3.827152 | 22.5 |
| Nationals | 3.794958 | 19.9 |
| Reds | 3.792506 | 16.5 |
| Pirates | 3.792193 | 20.4 |
| Giants | 3.769694 | 31.5 |
| Braves | 3.753880 | 11.4 |
| Brewers | 3.741721 | 11.1 |
| Phillies | 3.740204 | 7.1 |
| Rockies | 3.732665 | 9 |
| Diamondbacks | 3.717713 | 23.7 |
| Marlins | 3.714039 | 15.7 |
No surprise that four of the top five teams in Pitches/PA are playoff bound and among the leaders in Wins Above Replacement (WAR).
So, we’ve seen that a team’s Pitches/PA has a role in its offensive success. However, I still haven’t explained why it leads to more runs and success. For that, let’s look at another Epstein quote: “We haven’t had too many starting pitchers get deep into the games against us unless they have a Cy Young on their resume. And you can see in the third or fourth game of series that bullpens are worn out against us.”
As the Cubs see more pitches each at bat than every other team in baseball, they force starting pitchers to work harder than any other team. And as starting pitchers inevitably leave the game early, bullpens are asked to cover more innings than normal. This all means that the Cubs end up scoring more runs.
Patience in Practice
A great example of the Cubs’ approach at the plate came on September 18. On that day, the Cubs faced the Cardinals and Lance Lynn. Over his career, Lynn has proven to be a quality pitcher (3.38 career ERA). But, he does have problems with walks (3.33 BB/9). Knowing this, the Cubs forced Lynn to throw 83 pitches over just 3.1 innings. Lynn walked six batters while giving up three runs. After his quick exit, the Cardinals were forced to use its bullpen to cover 5.2 innings. With Lynn out of the game, the Cubs walked five more times and scratched two runs across in the fifth and three more in the sixth. Final score: Cubs 8, Cardinals 3.
As Theo states, Pitches Per Plate Appearance isn’t a perfect stat. Offensive statistics such as OBP and Runs Created can paint a more holistic, well-rounded picture than simply using P/PA. However, it has proven to be an extremely helpful metric for Epstein and the Cubs in 2015.