Daily Dictionary: Ground Ball%, Fly Ball%, Line Drive%

Daily Dictionary: Ground Ball%, Fly Ball%, Line Drive% (GB%, FB%, LD%)

The concept behind these statistics is extremely simple. Each three of these statistic measures the percentage of time a batted ball results in the particular outcome. While simple, these statistics are exceedingly important. We discussed previously how BABIP is a good predictor for hitters in terms of how lucky a particular hitter has been over a certain sample size. Unlike pitchers, though, hitters have a certain amount of control over their BABIP. In that sense, it is better to compare a hitter's current BABIP to his career BABIP. These peripheral statistics help us show why certain hitters have higher BABIP than others, and can help us predict even better if a hitter has been especially lucky in a particular year.

Line drives result in hits 74% of the time.

Ground balls result in hits 28% of the time.

Fly balls result in hits 21% of the time.

Accordingly, a hitter with a higher line drive percentage is going to have a higher than normal BABIP. Hitters with high fly ball percentages are going to have a lower than normal BABIP. Ground ball percentages are going to result in different outcomes for different players because of their individual speeds.

One hitter that has an abnormally high BABIP is Ichiro Suzuki with a career .356. His peripherals are as follows:

LD%: 20.3

GB%: 55.7

FB%: 24.0

Now, if we assign the percentage of the time those plays result in hits on average, we get:

(.203*.74)+(.557*.28)+(.24*.21) = .356

Now, those numbers aren't going to work out that nicely every time, but it will give you a general idea of how and why a hitter's BABIP is what it is. In Ichiro's case, his BABIP is extremely high because he hits a lot more ground balls than fly balls. Most hitters hit more fly balls than ground balls. Curtis Granderson is one of those guys:

LD%: 20.4

GB%: 35.7

FB%: 43.9

So, Granderson hits about 20% less ground balls and 20% more fly balls than Ichiro. Because Granderson hits a less optimal result more often, his career BABIP is significantly lower at the rate of a career .313.

So what does this all mean? When we're looking at a player who has a significantly higher or lower BABIP than his career BABIP, we should also look at his LD%, GB%, and FB% to see how those numbers correspond with his career. If a player has a higher BABIP than usual and his peripheral statistics are similar to his career averages, he might just be getting lucky. If his fly ball rate is higher than usual, there's a good chance he's getting lucky with regard to fly balls resulting in home runs. If his line drive rate is higher than usual, he's probably just hitting the ball better.