Throughout xStats you see six categories of batted balls: DB, GB, LD, HD, FB, and PU. These categories are are defined by launch angle, with an emphasis towards separating balls with regards to their single, double, and home run rates. Generally speaking, these batted ball types are displayed as a fraction of the total balls in play (GB%, LD%, etc). It is important to note these numbers are not necessarily predictive, and GB, LD, and HD have very weak Year to Year correlations. Dribble Balls (DB) are very predictive, while the Fly Balls (FB) and Pop Ups (PU) groups are reasonably weak although still somewhat reliable.
| Year to Year Correlations | ||||||
|---|---|---|---|---|---|---|
| Years | DB | GB | LD | HD | FB | PU |
| 2015-2016 | .729 | .042 | .119 | .165 | .483 | .554 |
| 2015-2017 | .730 | .199 | .153 | .192 | .435 | .621 |
| 2016-2017 | .758 | .242 | .122 | .155 | .432 | .574 |
However, these batted ball types were never meant to be used as a predictive tool, but rather as a descriptive one. In particular, they are designed to group players who have created similar contact. When combined with exit velocity, strike out rates, and value hit rates you can narrow down on particular types of batters, which can be useful in many different ways.
These batted ball categories are designed to be a filter, not a predictive tool. Even still, it is good to know the average stats for each of these sit types of batted ball. This morning I updated these figures on the Glossary page, so make sure to check that out.
Moving on from that, you may be curious about the real world stats for individual batters in each of these six categories. Below I have 12 charts, two for each batted ball type, which display the top 30 batters ranked by total Balls In Play and wOBA. Note that the wOBA charts have a minimum of 20 BIP. All of the numbers are from the 2017 season.
Dribble Balls Sorted by BIP
Many of the guys on this list are speedsters. Dee Gordon, LeMahieu, Yelich, Inciarte, Simmons, Gardner, Altuve, and Lindor, to name a few. Most of these guys are aiming to either hit the ball into the ground (Gordon) or on shallow line drives (Yelich). The natural result of which will increase the DB rate, whether intentionally or otherwise. Others on the list simply produce such a huge volume of balls in play that DB occur by chance (Altuve).
Dribble Balls Sorted by wOBA:
This list is a little more puzzling. Many of them are sluggers, so perhaps infielders have a deeper average position, leading to more hits on weakly hit balls. There are a few batters here who are fast runners (deShields, Kiermaier, Bellinger), so they may simply be beating out balls using their legs. However, considering that this list is mostly composed of harder hitting batters, clearly Exit Velocity is playing a large factor.
Ground Balls Sorted by BIP:
The Ground Ball batted ball type is difficult to write about, since it depends on context. It is difficult for a power hitter to have a good season without hitting a certain minimum number of Ground Balls; you cannot live off Dribble Balls, their success rates are too low. On the flip side, batters who hit too many Ground Balls are generally lacking in power. It is all about balance.
Ground Balls Sorted by wOBA:
This is not a great list of players, which I think points towards the contextual component of the GB type. Most of these batters had mediocre seasons, with a few obvious exceptions. You see Judge making his mark, his success on this batted ball type is likely what helped sustain his high batting average. Nelson Cruz and Tommy Pham also had solid seasons. Generally speaking, though, you don't want GB wOBA to be your claim to fame, it isn't valuable enough.
Line Drives Sorted by BIP:
Line Drives are the second most valuable batted ball type, and only slightly less valuable than the High Drives. Due to the physics of baseball batters often create their maximum Exit Velocity in this range of launch angles. As a result, even batters with lower average Exit Velocities can have good success rates on their Line Drives.
Line Drives Sorted by wOBA:
Elite power hitters can have production in one of three areas: Line Drives, High Drives, and Fly Balls. Generally speaking, the guys with the highest exit velocity live in the Line Drives range, and that is why you see Judge and Stanton on this list. I find the other names on this list a bit confusing. You have a few upcoming power hitters like Bellinger and Bryant. Then you have relatively weak hitters like Mike Zunino and Alcides Escobar. It is a weird list.
High Drives Sorted by BIP:
High Drives are the most valuable of the six types of batted ball. They are hit on angles that promote doubles and home runs, and are generally hit with an excellent Exit Velocity. This group of batters contains many elite hitters: Arenado, Betts, Altuve, Bryant, Votto and Blackmon. Wow, what a group of names. You want to hit as many balls in this area as you can, they are very valuable.
High Drives Sorted by wOBA:
Yowzers. Look at those wOBAs! Look at those batting averages! Donaldson hit over .900! The chart speaks for itself. Hit more HD.
Fly Balls Sorted by BIP
Most of the players on this list are great hitters. Hitting more of these types of balls is clearly a positive sign. Obviously Exit Velocity is also important, so you should set an appropriate minimum Exit Velocity before looking at this group, so you can weed out batters like Eduardo Escobar and Kevin Pillar.
Fly Balls Sorted by wOBA
Most of the batters on this list are elite batters, especially once you set a higher threshold for minimum BIP.
Pop Ups Sorted by BIP
This is obviously the weakest batted ball type. They are almost guaranteed outs, very occasionally carrying enough to leave the park or bounce off the ball for a double. You do not want to hit many of these balls.
Pop Ups Sorted by wOBA
Not even sorting by wOBA (which we can likely attribute to luck) can make the PU type seem redeemable. Devers hit three homers in this launch angle range. Gallo hit four. Good for them, I guess. You don't want to hit these balls, you want to lower the launch angle into a Fly Ball or ideally a High Drive.