The Age of the Ambush
The Effectively Wild podcast gets a good number of emails every day, and a recent one was sent along by Aidan Jackson-Evans. He was asking about a trend that he noticed, and wrote about several days ago. I’d like to point you to his post, at High Heat Stats. You should read it, because this thing is quickly just building off that. I wouldn’t have noticed this trend if not for the email, and he’s already done a lot of the work.
I’ll get to the heart of the matter. At FanGraphs, we have splits going back to 2002. That’s not very long, but it’s long enough for research purposes. In this plot, you simply see league wOBA by leadoff hitters, and overall league wOBA. Nothing complicated, at least if we’re all to the point where we no longer think of wOBA as being complicated.
Last year, leadoff hitters were better than average. The same was true the year before that, and the year before that. And so on. Nothing earth-shattering. This year, the numbers have been exactly equal. Here’s where things get cooler. In here, leadoff-hitter wOBAs, split by whether it’s the first plate appearance of the game, or a subsequent plate appearance.
Allow me to translate that! Between 2002 – 2015, leadoff hitters averaged a .323 wOBA in their first plate appearances. Over all the rest of their plate appearances, they averaged a .325 wOBA. Essentially the same. Nothing weird. But since the start of last season, leadoff hitters have averaged a .343 wOBA in their first plate appearances. Over all the rest of their plate appearances, they’ve averaged a .323 wOBA. Leadoff hitters, in other words, have started performing a lot better in the top and bottom of the first inning. This is what Jackson-Evans found.
So what’s going on? As with everything in baseball, the answer is presumably complex. Yet, using data from Baseball Savant, I bet I can simplify. Firstly, let’s look at the rate of pitches thrown within the Gameday strike zone. Here you see two rates: the league overall rate, and the rate for first plate appearances.
The first batter of the game sees more strikes. But this might not seem very dramatic. It’s not! This is dramatic. Here’s the same as above, but showing fastball rates instead:
Over the past decade, over all plate appearances, hitters have seen an average of about 57% fastballs. However, leadoff hitters in the first inning have seen an average of about 73% fastballs. The margin so far this season is 72% to 55%. It’s particularly extreme if you look at the first pitch of the first plate appearance, where pitchers routinely throw fastballs more than nine-tenths of the time. Pitchers have historically been aggressive to start off, trying to get into the flow of things. If the results are any indication, leadoff hitters have started to ambush more often. That is, instead of letting pitchers get away with free strikes, those leadoff hitters in the first inning are going up more prepared to take a swing or two. It’s as if the hitters are getting ready before the pitchers are.
It’s weird to see it happen so suddenly, but this is where we are after thousands upon thousands of plate appearances. It’ll be interesting to see if pitchers try to adjust by folding in more secondary stuff at the beginning. It’s the obvious apparent correction, but it might not make them feel very comfortable. Maybe they want or need to settle in with a few early fastballs. It’s something for all of us to try to monitor, I suppose. Kudos to Jackson-Evans for identifying this curiosity.
Jeff made Lookout Landing a thing, but he does not still write there about the Mariners. He does write here, sometimes about the Mariners, but usually not.
I wonder if this is why we are seeing less traditional leadoff hitters batting 1st in the order like Schwarber, Conforto, etc. because these players can better take advantage of the high fastball rate?
Bryant at one point as well. Good point.
Everyone just wants to be Alcides Escobar in Game 1 of the 2015 World Series
“It’s particularly extreme if you look at the first pitch of the first plate appearance, where pitchers routinely throw fastballs more than nine-tenths of the time.” When I started reading the article, I was expecting it to be more about this phenomenon and thinking hitters had started just teeing off on first pitch fastballs. I wonder if most of the leadoff difference is based on hitters knowing a fastball is coming first pitch.
Whoa
I was hoping this would be about charging the mound from first base. Joking aside, I enjoyed the article. Thanks.
Fewer managers are asking their leadoff hitters to work counts. See fastball- hit fastball. Pitchers are still going to do their best to get ahead, and now that many hitters are coached to be more aggressive, that can backfire.
That emailer has no future in the big leagues with that hyphenated name
People downvoting this don’t listen to EW
What I’d like to see in the above analysis is: Is there an increase in swing % in the first plate appearance for leadoff hitters? Is there a drop in walk rate that is being overcome by production on BIP that is producing a net positive in wOBA?
This wOBA also reflects Schwarber’s 36 PA leading off in the first inning with a .230 wOBA.
What about eliminating Springer’s and Schwarber’s wOBA to see the average w/o extremes?
George Springer has a .440 wOBA leading off the start of games.
I would be interested to see how much of the increase in first AB wOBA is due to an increase in leadoff home runs.
Why does wOBA give slightly more value to HBPs than to BBs?
HBP also includes TWTW because you are taking one for the team.
I believe it’s because BBs tend to be distributed in ways that are less likely to hurt the team on defense (intentional and “unintentional-intentional” walks tend to happen when there’s a base open so the runners don’t advance, or to bring the pitcher to the plate, etc). While HPBs tend to be pretty random and thus are more likely to cause runners to advance or potentially force in a run.