Getting The Most Out Of Batted-Ball Data: The Basics

The modern baseball statistical analysis revolution has largely been about one thing; weeding out the noise, and getting to the root of a player’s true talent. DIPS theory, which posited that the only things that pitchers truly should be held accountable for were strikeouts, walks and homers allowed, represented a major step forward, and brought terms like BABIP and FIP into the game’s lexicon. What those new metrics assumed, however, was that all other batted balls were more or less created equal. Now, with the advent of StatCast, we all know, publicly, that is not the case.

Granular batted ball data is making its way into the public domain, bringing with it the clarity that can overcome the limitations of many of the game’s newly accepted metrics. This article is the first of a short series that aims to prep you for the ongoing batted-ball revolution.

First, a very brief general history. The 30 individual clubs have been receiving detailed data regarding every pitch thrown in the major leagues since 2008. Most of you are familiar with Pitch f(x), which has been publicly available since then. The batted-ball data – hit f(x) – has not been publicly available. This year, MLB began utilizing a new data provider for StatCast, and has made the data available for MLB At Bat Premium subscribers. From my experience working with the data produced by both providers, the new StatCast data “runs” faster by a few MPH. Any specifics I refer to in this piece are based on the pre-StatCast data; it should just be used as a point of reference moving forward.

Before we can get to the fun stuff, we have to wade through some of the relatively mundane, if only to put some parameters in place. Let’s first define the major batted-ball types by vertical exit angle. At what point does a pop up become a fly ball, a fly ball become a line drive, and a line drive become a ground ball? I attempted to reconcile the detailed batted-ball data with official game accounts, and came up with the following breakdown:

– Popups = > 50 degree vertical angle
– Fly Ball = 20-50
– Line Drive = 5-20
– Ground Ball = below 5

Now that we’ve got the basic categories separated, let’s see how major league batters performed on each batted-ball type during the 2014 season.

– Popup = .015 AVG-.019 SLG (7.7%)
– Fly Ball = .275 AVG-.703 SLG (28.0%)
– Line Drive = .661 AVG-.869 SLG (20.9%)
– Ground Ball = .245 AVG-.267 SLG (43.4%)
– All = .323 AVG-.496 SLG (100.0%)

The above production figures cover about 95% of all batted balls struck in the 2014 season. The other 5% did not register on the recording equipment; most of them were weakly hit. The actual MLB production on all BIP in 2014 was .318 AVG-.489 SLG. It’s not perfect, but I’ll take a 95% sample of batted balls any day when setting out to do valuable research.

There’s some very valuable base-level information in that simple table above, and it yields strings that when pulled lead to even more eye-opening data.

First, the humble popup. It’s pretty much every bit an automatic out as the strikeout. It is a true, repeatable skill, for a pitcher, and flaw, for a hitter. Chris Young had an absolutely ludicrous 21.3% popup rate last season. The FIP calculation basically ignored this, giving him a 5.02 mark. Based on granular batted-ball data, I calculated a “tru” ERA for all 2014 ERA qualifiers; Young’s mark was a more reasonable 4.37, which credited him for his popup prowess, while docking him for the illusory benefits of his friendly Safeco home park.

Most power hitters have higher than average popup rates; their additional power justifies the additional automatic outs. More interestingly, a low popup rate, along with a high contact rate, is the key to becoming a .300+ hitter. Now, we all know Derek Jeter was toast last year, a shell of his former self. Still, though he couldn’t hit the ball nearly as hard as he once did, you could still see the basic outline of his exceptional offensive game. He struck out only 13.7% of the time, and had a popup rate of only 1.7%. Accompanied by league average frequency and authority marks in the other batted-ball categories, Jeter would have batted .300 again. Along with Jeter, the three other AL regulars with the lowest popup rates were Joe Mauer, Howie Kendrick and Michael Brantley, three other batting average-centric players.

Popups are the one batted-ball type in which exit speed matters not one whit; it’s all about frequency. As you might imagine, authority is a much bigger deal with regard to fly balls, as there is a relatively fine line between the ultimate upside, a home run, and a garden variety out. If you take one piece of information out of this article, let it be the following one:

– Fly Balls > 92.5 MPH = .560 AVG-1.884 SLG (7.6% of all batted balls)
– Fly Balls 75-90 MPH = .077 AVG-.148 SLG (11.9%)

That’s pretty staggering. The upper boundary of the second group is just 2.5 MPH shy of the lower boundary of the first. I call the second group the Donut Hole. It is where many careers go to die. Attrition due to injury, age, or any number of factors gradually drives hitters out of the first and into the second group.

Production on fly balls varies greatly from field sector to field sector, and from ballpark to ballpark. In a future article, we’ll drill down and look at the magnitude of some of those variables. For now, let’s put those aside and simply focus on some important facets of fly ball frequency and authority.

You’ll notice from one of the earlier tables that there were far more grounders (43.4%) than fly balls (28.0%) in the majors last season. This disparity has increased in recent seasons as clubs have focused on ground ball pitchers. By definition, then, it is quite unusual for a player to hit more fly balls than grounders. Only 9 of 77 2014 AL batting title qualifiers did so, along with 5 of 65 NL qualifiers. In recent seasons, virtually all hitters meeting this criteria declined in performance the next season, many precipitously. It’s simply not natural for a major league hitter to hit more fly balls than grounders over the long haul, and fewer fly balls obviously leads to less longball power.

For each 2014 MLB batting title qualifier, I came up with a “contact score” for each BIP type, with 100 representing MLB average. Take every batted ball, place it in a neutral context, apply run values, etc.. As one might expect, the fly ball contact scores vary much more widely than those of any other BIP type. Three qualifiers actually cracked a 300 fly ball contact score last season; Giancarlo Stanton (407), Chris Carter (329) and Chris Davis (321).

How hard did they hit the ball in the air? Remember, it is at 92.5 MPH where fly balls begin to do real damage. 27.2% of all fly balls were that hard in 2014. Stanton hit 101 fly balls, and fully 54 of them (53.5%) were hit at least that hard. But wait; 33 of those 54 were hit at 100 MPH or harder, and 14 of those were hit at 105 MPH or higher. Only 0.59% of all fly balls were hit at 105 MPH or harder last season; 13.9% of Stanton’s were. An even higher percentage of Carter’s fly balls (55 of 102, 53.9%) were hit at 92.5 MPH of higher, though he reached 105 MPH only 7 times. Davis reached the 92.5 MPH threshold on 53.5 of his fly balls (47 of 88), though he reached the 105 MPH mark only four times.

Of the three players, Stanton has the most room to grow his fly ball rate, as his 28.1% mark basically matches the MLB average. Carter, however, is one of the nine 2014 AL batting title qualifiers to hit more fly balls than grounders, marking him as a candidate for 2015 decline, which seems a pretty safe bet based on the early returns. And Davis? Well, he hit way more fly balls than grounders in his 2013 career year, and experienced his predictable decline last season despite his prolific fly ball contact score. Similar damage per fly ball, just a lot fewer fly balls.

Next, on to line drives. On the surface, they’re kind of boring, though very productive. Hit a line drive, you probably get a hit, and it rarely goes over the fence. It’s the most random of the batted ball types, with the most variation from year to year. Two of the lowest line drive rates in the AL last year belonged to Alex Gordon and Josh Donaldson, both at 17.3%. Ditto Andrew McCutchen (17.6%) and Hunter Pence (17.5%) in the NL. I’ll take any of those guys on my squad any time, and wait for the positive regression of their liner rates.

Still, some players skillfully post high liner rates on an ongoing basis; Miguel Cabrera, Michael Brantley, Robinson Cano, Joe Mauer, Buster Posey, Matt Carpenter, Freddie Freeman and Adrian Gonzalez are some very unsurprising examples of this, but would you believe that James Loney and David Freese annually rank among league leaders in liner rate?

Only 176 line drive homers were hit in 2014. If you want to hit one, you have to hit a liner at least 97.5 MPH, and even then you probably to need to hit it down the line in one of a number of relatively line drive friendly ballparks. Once you get below 97.5 MPH, you actually have the best chance of getting a hit between 75-80 MPH then at any other velocity interval. Batters hit .739 AVG-.820 SLG on 75-80 MPH liners last season, while batting only .637 AVG-.825 SLG on 87.5-90 MPH liners. Problem is, the harder hit ones carry to the outfielders more often. Still, you’re batting at least .635 on liners all the way down to 70 MPH, and you’re still at .547 AVG-.579 SLG from 65-70 MPH.

Hitters only get into trouble on liners below the 65 MPH mark, where the liners are more of the broken bat variety, and can usually be hauled in by the infielders. Batters hit .218 AVG-.238 SLG on liners below 65 MPH last season.

Individual hitters’ line drive “contact scores” vary much less than those of fly balls, as you might expect. The 2014 MLB leading liner contact scores belonged to Stanton (148), Ian Desmond (147) and Jose Bautista (137). To get a feel for just how hard Stanton hit his line drives, consider this: exactly 1.64% of MLB liners were hit at 105 MPH or higher last season; 30.1% (22 of 73) of Stanton’s were.

Lastly, we have ground balls. When a ground ball was hit at 95 MPH or higher last season, batters hit .532 AVG-.583 SLG. When hit at 70 MPH or less, they hit .116 AVG-.123 SLG. Everywhere in between, they hit .340 AVG-.375 SLG; it was all in the luck of finding a hole in the infield.

When it comes to ground ball performance, it’s just as important to avoid hitting a weak ground ball as it is to hit a hard one. To demonstrate this point, consider the two hitters with the best grounder contact scores last season, the unlikely pairing of Miguel Cabrera and Aramis Ramirez. 12.91% of MLB grounders were hit at 95 MPH or higher last season. Cabrera reached that mark on 32.1% (59 of 184) of his grounders, en route to compiling a grounder contact score of 203. Ramirez only reached that threshold on 20.3% (30 of 148) of his grounders, and posted a grounder contact score of 176.

Both were quite good at avoiding the weak, “roll-over” ground ball. 53.53% of all MLB grounders were hit at 70 MPH or less in 2014; only 43.2% of Ramirez’, and an amazingly low 32.1% of Cabrera’s were. How big of a problem can the roll-over grounder be? Ask Ryan Howard, who hit 61.9% of his grounders at 70 MPH, the vast majority to the dead pull side. Ground ball pulling and resulting infield overshifting is a very significant topic that will covered in more depth in another article. The contact scores referenced here for Cabrera and Ramirez do not take the effects of excessive pulling into account. Cabrera does not pull excessively on the ground, so his 203 contact score is legit. Ramirez, on the other hand, is an excessive ground ball puller, and his contact score needs to be docked somewhat.

Pitchers do not control contact authority to the extent that hitters do, obviously, but at the extremes there are clear cases of good and bad contact management. With regard to grounder contact management, one name that must be discussed is Dallas Keuchel. Those of you have been reading my articles know that I have been a Keuchel guy for quite awhile, and here’s why. First, don’t walk people. Second, post the highest grounder rate, by far, among MLB ERA qualifiers in 2014. Third, post the 5th lowest grounder contact score (77) among 2014 MLB ERA qualifiers. The skill set was already in place, and last season, Keuchel put all of the pieces together. Fully 62.3% (210 of an amazing 337) of the grounders allowed by Keuchel were hit at 70 MPH or less.

One of the four pitchers who posted a lower grounder contact score than Keuchel last season was Johnny Cueto (75). While one can look at pitchers like Felix Hernandez and Clayton Kershaw immediately and identify multiple reasons why they are great, it’s a bit more difficult to do so with Cueto. He does everything in an above average fashion, but the one facet of pitching where he can be considered truly great is in limiting ground ball authority. 59.8% of the grounders allowed by Cueto last season were hit at 70 MPH or less.

Batted-ball data can easily be misinterpreted, but once you understand its nuances, it is an exceptional aid in talent evaluation. Just looking at a player’s average exit speed on all BIP types can be very misleading; hitting a bunch of 90 MPH fly balls doesn’t get you much of anywhere. Being able to weave together the intricacies of frequency and authority, while taking into account pull tendencies, park effects, etc., enables one to combine such new-school information with older-school traditional scouting to create a more complete, valid portrait of the modern ballplayer.