“They Don’t Pay Me to Hit Ground Balls”

Examining MLB’s Obsession with Launch Angle

“They Don’t Pay Me to Hit Ground Balls”

My previous blog centered around a tweet from Jayson Stark where he suggested that the 2018 Major League Baseball season was on pace to produce 10,000 less batted balls in play than were recorded in 2009. My analysis suggested that even though homeruns had increased by 10.4% over that time frame, strikeouts had increased by a whopping 25.3%. I suggested that analytics may be to blame as managers rely more and more on the numbers to dictate when to make a pitching change, to exploit pitcher vs. batter match-ups. I also suggested that pitchers had the advantage over the hitters because they were fresher, and they consistently throw pitches in the mid to upper 90 mph. All this could be true, but one commentator suggested more than what I mentioned above – the real reason for the increase in strikeouts was MLB hitter’s new obsession with launch angle.

According to MLB’s Statcast glossary, Launch Angle represents the vertical angle at which the ball leaves the player’s bat after being struck. So why is this such a big deal? Historically coaches have preached for batters to stay on top of the ball – which means lower launch angles and in general, ground balls. But things are starting to change! In a 2016 interview on MLB Network, Toronto Blue Jays slugger Josh Donaldson was asked – What is one piece of advice that he would share with a 10-year-old hitter today? He said, “If your coach tells you to stay on top of the ball, tell him NO, because in the big leagues, these things that they call ground balls are outs. They don’t pay you for ground balls. They pay you for doubles, they pay you for homers”. Hence the obsession with launch angle.

I wanted to look further into the launch angle debate, so I grabbed Statcast data for the 2015-2018 seasons. Here is what the data told me.

Average Launch Angle by Year

I took the launch angle data for every batted ball (hits and outs). There has been a steady increase of launch angles in each of the last 4 seasons. In 2015, the average launch angle was 10.53 and in 2018, the average launch angle has increased to 12.13 – a 1.6% increase.

Batted Balls in Play by Contact Type

In the Statcast Data, there is a field which denotes the batted ball type. I grouped the types into two buckets, ”Hit in the Air” (Line-Drive, Fly Ball, Pop Up) and “Hit on the Ground” (Ground Balls). The data shows that after the 2015 season, the number of balls hit in the air are higher than the number of balls hit on the ground. This increase indicates the switch in hitting from staying on top of the ball and hitting ground balls to getting under the ball and producing line drives and fly balls. Given the increase in strikeouts each year, one could deduce that maybe the increased launch angle approach is an all-or-nothing proposition.

Identifying the Ideal Launch Angle

I grouped the various launch angles into buckets based on a launch angle guide that MLB had on their site. The buckets are as follows:

Ground Ball: Less than 10 degrees

Line Drive: 10-25 degrees

Fly Ball: 25-50 degrees

Pop-up: Greater than 50 degrees

Here is what the data said:

Less than 10 Degrees

The data tends to lend credence to Josh Donaldson’s argument about saying NO to staying on top of the ball. Out of the 216,022 balls hit into play, 156,404 (72.4%) of the batted balls are at less than 10 degrees (ground balls) turned into outs.

10-25 Degrees

A hitter who is keen about getting a hit should concentrate on producing a launch angle between 10-25 degrees. Almost two-thirds of the 95,546 balls hit into play in the range resulted in a hit. Single: 36.14%. Double: 19.92%, Triple: 1.89%, and Home Run: 6.11%

25-50 Degrees

This is where the power hitters tend to live. The data suggests that this is the feast or famine range. Of the 93,713 (24.67%) balls hit into play that resulted in a hit, 13,199 (14.08%) of those were home runs.

Greater than 50 Degrees

As a hitter, you don’t want to live in this range. Of the 36,795 balls hit into play, only 476 (1.53%) resulted in a hit and none of those was a home run.

Here is the data in a table format.

Next time you are watching a baseball game, keep an eye out for the launch angles of the hitters. Watch the approach of the different types of hitters – the power hitters will have the higher launch angles (and more home runs), the hitters with the higher batting averages will fall in the 10-25-degree range, and those hitters who are grounding out are still trying to stay on top of the ball. Unfortunately for those players, in today’s game, they don’t pay to hit ground balls. Here is a link to the app where you can find your own insights. Enjoy!

What's with the #MLB's new obsession with Launch Angle's? Chuck Bannon is putting data to work to find the answer!


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