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The Marlins have embraced the defensive shift

Bolstered by a new analytics department, the Marlins’ defensive strategy has shifted (what a pun).

MLB: Cincinnati Reds at Miami Marlins Steve Mitchell-USA TODAY Sports

Sliiiiiide the left, sliiiiiide to the right....

If you have danced the Cha-Cha Slide, you have essentially performed a baseball shift. Sliding fielder position to the left, right, or “taking it back now (y’all)” when a batter like Giancarlo Stanton comes to the plate has become an increasingly common practice around the league. Despite declining to shift for many years, the Miami Marlins recently embraced the trend.

The shift is a defensive strategy in which fielder position is adjusted in response to a specific batter. The theory is that the defense is playing the percentages—if a specific batter always hits to right field, moving more players to that location will likely result in an out.

As an example, let’s take a look at Curtis Granderson’s spray chart from 2018. He was among MLB’s most frequently shifted players, according to Statcast. Each dot on the chart represents a ball that was hit into play:

Figure 1. Curtis Granderson 2018 spray chart

The first thing that jumps out from this image is that Granderson pulls the ball. The second thing is that he pulls the ball on the ground. By deduction, if you just put everyone on the infield between first and second base, there is a high probability Granderson will be on the bench sooner rather than later. It is no surprise then that, of his 224 plate appearances where he put the ball in play, he faced the shift 200 times. 200!

Seems pretty simple, everybody is probably doing it...right? WRONG!

Oddly enough, the shift is one of the most contentious and confusing topics in baseball. Some people think the shift works, some people don’t think the shift works, and some people just hate the shift because they hate fun. There has even been talk of limiting shift usage.

Well, I’m not here to go down that rabbit hole. I am here to talk about the Marlins, and in particular, an interesting trend in the way the Marlins view the shift.

In 2016, the Marlins shifted during 1.6% of plate appearances, easily the lowest rate in baseball. The team with the next lowest shift rate that year, the Chicago Cubs, shifted on 4.6% of plate appearances. The MLB average was 13.8%.

In 2017, the Marlins mostly stuck with their Stone Age approach. They ranked 21st in shift frequency (8.5% of plate appearances).

However, in 2018, fresh off an overhaul of the analytics department, everything changed. The table below shows the three-year progression of the Marlins’ overall shift frequency, vs. right-handed hitters (RHH), and vs. left-handed hitters. The figure compares the overall frequency to league average.

Table 1. Shift frequency data for the Marlins from 2016-2018

Figure 2. Shift frequency per plate appearance: Marlins vs. league average

Look at that spike in 2018. The Marlins, after being a team that rarely shifted, did so on 22.5% of plate appearances. That number was the 9th-highest frequency in MLB last season, and well above the average shift frequency of 17.4%.

It’s no coincidence that 2018 was Miami’s first full year under new ownership. When speaking with Joe Frisaro last July, vice president of player development and scouting Gary Dembo—one of Derek Jeter’s many new hires—described the Marlins recent emphasis on analytics:

“The analytics department now has become one of the most valuable departments in the Marlins’ organization. The reason is, they’re affecting every single department. It’s pro scouting, amateur scouting, international scouting, baseball operations, the Major League team, and every one of our Minor League teams. It will have a major effect at the Trade Deadline as well.”

This is all well and good, but has the shift actually been working?

One way to analyze the results is batting average per balls in play (BABIP). BABIP measures how often a ball hit into the field of play—including catches made in foul territory and excluding home runs—falls for a hit. Over a full-season sample, this informs us about the effectiveness of a defense. A better defense is more likely to have a lower BABIP because more balls hit into play are converted into outs. One would also assume that shifting into optimal field positioning provided by the shift decreases opponent’s BABIP.

Let’s test that theory for the Marlins, specifically.

2016: .303 BABIP

2017: .298 BABIP

2018: .290 BABIP

So BABIP against decreased when the Marlins shifted more frequently. Wow! Success! The shift works!!!

While the numbers above are promising, they lack the depth we need to answer our question. How can be determine whether the shift was responsible for this defensive improvement?

To get a better answer, we need to look at the the BABIP against when the Marlins were shifted vs. when they were not shifted. From 2016-2018, the BABIP against when the Marlins shifted (.300) was actually slightly higher than when they didn’t shift (.296).

So the shift...doesn’t work? Or maybe it does? If you aren’t confused, then that makes one of us.

There are a number of additional factors to look at including pitcher effectiveness, prowess of individual fielders, opponent exit velocity, etc. Furthermore, there is growing evidence that batters are adjusting to the shift and increasing their launch angle to hit batted balls over the infield, including those hit for home runs.

The debate over the shift still rages on in the baseball community. We will have to trust that the Marlins analytics department knows what they are doing, that tailoring your positioning to the hitters’ tendencies is better than playing straight-up every play, that shifts do provide an advantage.

With Trey Hillman replacing Perry Hill as the new first base/infield coach, it will certainly be interesting to see how often the Marlins use the shift in 2019.

Data obtained from Fangraphs and the Baseball Savant.