The Yankees hit a lot of home runs, which is, in theory, very good news about their prospects. As you surely know, though, the team hitting a lot of home runs actually worries a lot of fans. There is a prevailing narrative around the game that offenses that hit a lot of home runs come up flat in October, and it’s one that comes up often around the Yankees specifically.

I found myself thinking about this debate a lot this weekend as the Yankees took on the Dodgers and thought it was a good time to highlight some research that’s already been done. Let’s get right into it, shall we?

The Yankees in Context

Let’s start by stating the obvious: the Yankees hit a lot of home runs. And I mean a lot. I think we all agree that the current Yankee “window”, if you will, officially opened on Opening Day 2017. Here are the top 5 home run hitting teams since that day:

New York Yankees: 752 Los Angeles Dodgers: 685 Oakland Athletics: 669 Houston Astros: 665 Milwaukee Brewers: 650

The Yankees have 67 more home runs than the second-closest team on the list in the same amount of games. Of course, much of that is powered by last year’s historic home run surge, when the Yankees set the single-season record for team home runs in a year. (That record will be broken again this year, barring an unforeseen apocalyptic event.)

There was something else notable about last year’s team, too, though. The 2018 Yankees became the first team in MLB history to record at least 20 home runs from all 9 lineup spots over the course of a season. That’s a showcase of some serious depth, but it also suggests that the front office is consciously building a team with power, from top-to-bottom.

Although the 2019 Yankees aren’t quite as legendary as the 2018 version–yet, anyway, as they have hit a record number of home runs in August–they are still a sight to behold. Check out the 2019 home run list:

Minnesota Twins: 253 New York Yankees: 244 Los Angeles Dodgers: 229 Houston Astros: 222 Atlanta Braves: 210

The Yanks have been out-slugged by the Twins so far. The gap is closing, but it doesn’t really matter: the Yankees are clearly in a league of their own when it comes to power. And last night, Mike Ford hit 2 HR from the 9-spot in the lineup, which made it 20+ HR from each lineup spot for the 2nd consecutive season. As I noted on Twitter before the game, they have an outside chance at 30+, depending on the lineup construction when some big names return.

Speaking of, it is notable that they’ve done this with marquee slugger Giancarlo Stanton playing in just 9 games and with other power hitters like Aaron Judge, Gary Sánchez, Edwin Encarnación, and Luke Voit each missing significant time. The Yankees are powerful not just across their lineup, but throughout their organization. If a team wanted to maximize its chances to hit a home run in each individual at-bat, regardless of context or situation, it would be constructed an awful lot like the Yankees.

Anyway, all that really matters for this exercise is the fact that the Yankees hit many more home runs than most other MLB teams–even the good ones! I think it’s fair to say that this trait is not simply a result of the juiced ball. It is a multi-year trend and it is one that is clearly a result of a strategic choice by the front office to target home run hitting players.

The Guillen Number

With that in mind, let’s take a quick look at Baseball-Prospectus’ “Guillen Number.” The Guillen Number tells us the percentage of overall runs scored via the home run. It is, in other words, a way to quantify a team’s home run “reliance.” As you might imagine, a pretty high percentage of the Yankees’ runs come via the home run. Here is the Yankees’ Guillen Number in 2017, 2018, and 2019, respectively, with their league ranking in parentheses:

2017: 46.74% (6th)

46.74% (6th) 2018: 50.76% (1st)

50.76% (1st) 2019: 49.35% (8th)

But it’s funny, isn’t it? No team even approaches the Yankees in raw home run totals from 2017-2019–NYY led the league in HR in 2017 and 2018 and rank 2nd this year, remember–and the Yanks they only crack the top 5 in this category once. Much like the infuriatingly persistent myth that the 2019 Yankees strike out less (22.6% K rate) than the 2018 version (22.7%), the idea that the Yankees are overly-reliant on the home run simply doesn’t stand up to the slightest statistical scrutiny. (I don’t buy it conceptually anyway, but even if it were plausible, the Yankees would have to sit way atop the league for it to matter, no?)

Finally, there is a link between hitting home runs, scoring a large percentage of runs via the homer, and a team’s success. As YES Network’s stats guru James Smyth has noted, across all of baseball history, playoff teams score 12% more runs than non-playoff teams, score a greater percentage of those runs via the home run (16% more) than non-playoff teams, and hit more homers overall (25% more).

Does hitting lots of dingers help you score more runs and get to the playoffs? Of course. There's more to it than just offense, but playoff teams have scored about 12% more runs than non-playoff teams, thanks in part to hitting 25% more homers (their Guillen Number is 16% higher) — James Smyth (@JamesSmyth621) March 18, 2019

The Guillen Number and the Playoffs

That all makes sense, right? Pretty straightforward stuff. I don’t think anyone doubts that good teams hit more home runs than bad teams. However, when it comes to October, the narrative changes a lot. And I mean a lot. There are two main arguments to support the idea that being overly-reliant on home runs dooms a team in the playoffs:

The weather is chillier in October, and baseballs travel farther during the heat and humidity, therefore you can’t count on hitting home runs in postseason play.

The competition is better in October, with better pitchers taking the mound each day and managers incentivized to use their top arms out of the bullpen, therefore you can’t count on hitting home runs in postseason play. (Also known as “the Yankees won’t play the Orioles in October.”)

We’ve all heard those two arguments time and time again. The only problem with them, of course, is that they’re completely and utterly false. They’re not false because of the underlying assumptions–baseballs DO travel farther in July and teams DO use better pitchers in the playoffs–but because of the simple fact that teams that hit more home runs tend to win more playoff games.

Fortunately for me, Smyth did a bunch of research on this already so be sure to check that out for a bit more info (it’s the thread highlighted above), but there are a few useful notes in there that are worth sharing here, I think. First, let’s look at the runs per game, homers per game, and Guillen Numbers of each playoff team from 1995-2018 in the regular season and postseason, courtesy of Smyth:

Reg. Season Playoffs Percentage Change R/Game 4.97 4.17 -16% HR/Game 1.15 1.06 -8% Guillen Number 37.2% 39.6% 6%

This builds off research done earlier at Baseball Prospectus by Ben Lindbergh and Dan Turkenkopf. The results are pretty clear. Teams score fewer runs in the playoffs and they hit fewer home runs…but a greater percentage of runs are scored via the home run in the playoffs. (There’s also no evidence to suggest that HR-reliant teams fare worse, either, as they’re 92-90 in 182 playoff series over this period.)

Here’s another chart. This one, also per Smyth, takes the 440 MLB playoff teams in the Wild Card Era and divides them into quadrants by their regular season Guillen Number. It then looks at the percentage change in runs per game in the playoffs and the corresponding change in Guillen Number:

Percent Change R/G Percent Change GN Top 110 -15% +2% Next 110 -17% +8% Next 110 -17% +11% Bottom 110 -27% +16%

This tells us two things. First, it tells us that, in the last 13 years of postseason play, scoring significantly decreases, as we’d expect, and it decreases across the board–but it turns out that run-scoring decreases *do* discriminate, but not in the commonly-thought way. Teams that hit fewer home runs–the “scrappy, manufactures runs” type teams–have a harder time scoring in October.

Second, it tells us that even teams who stay away from the long ball in the regular season but make the playoffs anyway tend to score more runs via the home run in October. The run-scoring environment is clearly such that HR-happy teams have fewer adjustments to make. Go figure.

Finally, let’s look at just World Series winners, again courtesy of Smyth:

Reg. Season Postseason Percentage Change R/Game 4.92 4.52 -8% HR/Game 0.81 0.86 +6% Guillen Number 26.6% 30.3% +14%

Again, this is pretty clear: fewer runs but more home runs, which means that teams actually rely on the home run to win in October. It also means that, because of the low run-scoring environment when the lights are brightest and the temperature coolest, you want to build a team that is already capable of hitting a lot of home runs. Better yet, you want your entire lineup, not just a few guys, capable of going deep. If power is the name of the game in October, then you want top-to-bottom, consistent power threads across the lineup to maximize your chance of winning the World Series.

Does that sound familiar to you, or is it just me?

An October Night in Late August

Last weekend’s series with the Dodgers was a pretty good illustration of these numbers in action, and it’s a window into the front office’s thinking. This was a potential World Series matchup that played like it, showing us exactly what it will take for the Yankees to win in October.

Think about it. They went up against marquee pitchers on Friday and Sunday in Hyun-Jin Ryu and Clayton Kershaw, with Ryu poised to win the Cy Young and Kershaw firmly entrenched as one of the finest pitchers in league history. In other words, they are the type of pitchers that come to mind when you think of a daunting October series. That it was on the road in Dodger Stadium–with all of the history and tradition that entails, particularly between these two teams–only added to the mystique.

And yet Yankees blasted Ryu for 7 runs on the back of 3 HR on Friday night, ultimately hitting 5 and winning 10-2. Both teams hit one home run on Saturday, with the Dodgers winning 2-1 in what was a contested finish. But then on Sunday, future Hall of Famer Clayton Kershaw took the hill with the series tied in Dodgers Stadium. He fanned 12 Yankees across 7 innings, walked none, and surrendered just 4 hits.

Of course, the story doesn’t end there. Of the 4 hits, 3 left the yard, and the Yankees won the game 5-1. They took the series from the two-time defending NL champions, twice beating dominant pitching with their home run power. It was their 18th win in their last 26 tries.