Author: Peter Lim (Weinberg ’21)

The 2017 Houston Astros and the 2018 Boston Red Sox.

These two World Series champions have an interesting resemblance. Yes, they both had Alex Cora (as bench coach for Houston, as manager for Boston), but other than that, both teams led Major League Baseball in runs scored during their respective regular seasons. For three years in a row, beginning with the 2016 Chicago Cubs, a high-scoring team with triple-digit regular season wins won the World Series.

2018: BOS (108-54) over LAD (92-71)

2017: HOU (101-61) over LAD (104-58)

2016: CHC (103-59) over CLE (94-68)

Below is a comparison of how each of these teams placed among all MLB teams in terms of runs scored in their respective seasons.

2018: BOS (1st) over LAD (5th)

2017: HOU (1st) over LAD (12th)

2016: CHC (3rd) over CLE (5th)

Speaking of the Red Sox, their offense made a huge improvement from last year: in 2017, they were 10^th in runs scored and 27^th (168) in team home runs, but in 2018, they were 1^st in runs scored and 9^th (208) in team home runs. Needless to say, the addition of J.D. Martinez (3^rd among all qualified players in wRC+) and the MVP-caliber season of Mookie Betts (2^nd in wRC+) was integral in this improvement. However, there was also a team-wide adjustment that made this progress possible.

Boston fired hitting coach Chili Davis prior to the 2018 season. During his three-year tenure with the Red Sox, Davis never mentioned the term “Launch Angle”—he is well-known for his old-school approach to hitting. Instead, the team named Tim Hyers as their new hitting coach for the 2018 season. As Boston’s minor league hitting coordinator from 2013 to 2015, Hyers was well-known for his expertise in launch angle, which got him a job as the assistant hitting coach for the LA Dodgers in 2016. Meanwhile, Davis has been fired after 1 year with the Chicago Cubs.

Indeed, Boston’s average launch angle went from 20^th (10.6º) to 14^th (12.2º) in all of baseball (1^st: OAK 14.7º, 30^th: SD 8.8º). Consequently, the team’s Barrels% went from below league average (4.9%) in 2017 to nearly twice as high (8.4%) this season. This is a big reason why Boston’s slugging massively improved in just one year. Xander Bogaerts was the player with the biggest improvement out of all of them, improving his launch angle from 8.2º (.273 .343 .403 10HR) in 2017 to 12.7º (.288 .360 .522 23HR) in 2018.

There’s another player in the Red Sox lineup that had an interesting year in terms of launch angle: J.D. Martinez. While J.D. was a major proponent of Hyers’ approach to launch angles, his average launch angle has actually decreased from last year (15.2º to 10.7º). This value is lower than those of many of his teammates, including Mookie Betts (18.5º), Andrew Benintendi (12.5º), and Jackie Bradley Jr. (12.0º).

A famous spray hitter, J.D. brought his contact point back a little since joining the Red Sox. This allowed him to send more baseballs right down the middle and to opposite field than he ever did. He also ended the season with a career high in batting average (.330) and brought his K/PA down a lot, from 26.2% last year to 22.5% this year. While his launch angle decreased, his exit velocity increased. He has made continued strides to improve his approach even after being an MVP-type player, and finally found what seems to be the most ideal launch angle for him.

J.D. Martinez (Pull% / Launch Angle / Exit Velocity / wRC+)

[2015] 41.1% / 16.0º / 91.2 mph / 136

[2016] 40.4% / 13.4º / 91.5 mph / 143

[2017] 38.3% / 15.2º / 91.0 mph / 167

[2018] 37.7% / 10.7º / 93.0 mph / 170

Martinez signed a five-year, $110 million contract with the Red Sox, and can opt out after each season starting next offseason. Now going into his age 31 season in 2019, Martinez’s success will depend on whether and when he will opt out, and how long he will be able to maintain his current prime form.

Betts (5-9, 180lb) needed a different approach to hitting than did Martinez (6-3, 220lb). To hit the ball hard and far with his smaller build, Betts needed to bring his point of contact way out in front. In fact, point of contact and launch angle has a very close relationship. This year, Betts pulled the most baseballs out of all of his major league seasons. This resulted in an improvement in both launch angle and exit velocity. The downside is that once you bring your contact point forward, you need to swing earlier, which inevitably makes your swing less accurate. This has not been a problem for Mookie, who has one of the best hand-eye coordination you can ever expect from a human being. The pivotal question is whether his body can withhold his dangerous swinging mechanics over the long run.

Mookie Betts (Pull% / Launch Angle / Exit Velocity / wRC+)

[2015] 40.3% / 14.8º / 89.9 mph / 120

[2016] 39.7% / 12.5º / 89.7 mph / 136

[2017] 44.4% / 14.1º / 88.4 mph / 106

[2018] 47.2% / 18.5º / 92.3 mph / 185

Another hitter to look at in terms of launch angle is Christian Yelich. As the first Brewer to win a batting title (.326), he also ranked 3^rd in HR (36) and 2^nd in RBI (110) in the league. If the regular season was just a week longer, Yelich (.352 .500 .807 in September) could very well have been the first National League player since Joe Medwick in 1937 to win the batting triple crown.

Yelich’s success indicates a new approach of hitting: “beating the shift.” Bryce Harper (.249 .393 .496), who had a disappointing season (considering his lofty standards) before going into free agency, had a BABIP of .289 (94^th out of 140 qualified batters) this season. Meanwhile, Yelich (.326 .402 .598) had a BABIP of .373, good for 2^nd between Martinez (.375) and Betts (.368). Harper’s BABIP was .356 in 2017.

The only difference between 2017 and 2018 for Harper is that he pulled more baseballs (2017: 35.5%, 2018: 42.3%), so opposing defenses shifted against him 51.6% of the time. The only player to have a .300 batting average or above while getting shifted over 50% of the time is Freddie Freeman (.309 .388 .505), a player with outstanding line drive hitting. Meanwhile, Yelich is known for his spray hitting, and hence is only shifted against 1.7% of the time, lowest of any 30 HR hitter this season. In other words, defensive shifts, a trend that has continued to increase for the past decade and have been the topic of study for many organizations, simply do not work against Yelich. This tells us that for a batter to be elite, he needs to hit a lot of home runs, avoid the shift, or both.

% Shifted Against

RHB: 1^st: Edwin Encarnacion (55.4%), MLB Average (8.9%)

LHB: 1^st: Chris Davis (91.9%), MLB Average (29.6%)

In his first two full seasons in the majors, Yelich hit 9 (2014) and 7 (2015) home runs. In the next two years, that number increased to 21 (2016) and 18 (2017). But nobody thought of him as a contender for the home run title. Two things happened to Yelich in 2018: he moved to a more hitter-friendly park and he increased his first-pitch swing rate from 19.4% in 2016 to 28.8% this year. It is no surprise that he led the majors in first-pitch home runs (12) this season.

Christian Yelich (Pull% / Launch Angle / Exit Velocity / wRC+)

[2015] 31.7% / 0.0º / 91.5 mph / 120

[2016] 36.0% / 2.5º / 92.4 mph / 134

[2017] 33.3% / 4.7º / 90.4 mph / 118

[2018] 34.9% / 4.7º / 92.3 mph / 166

However, there are still red flags in Yelich’s approach. His launch angle did not improve at all since last year and remains to be extremely below league average (10.9º). A launch angle of 4.7º is highly abnormal for a top power hitter.

2018 MLB HR Rankings (Launch Angle)

48 – Khris Davis (18.1°)
43 – J.D. Martinez (10.7°)
40 – Joey Gallo (21.5°)
39 – Mike Trout (18.5°)
39 – Jose Ramirez (18.8°)
38 – Giancarlo Stanton (11.6°)
38 – Nolan Arenado (15.4°)
38 – Francisco Lindor (14.5°)
37 – Nelson Cruz (12.8°)
37 – Manny Machado (14.4°)
37 – Trevor Story (15.7°)
36 – Matt Carpenter (20.4°)
36 – Christian Yelich (4.7°)
35 – Jesus Aguilar (16.2°)
35 – Max Muncy (17.8°)
34 – Bryce Harper (13.9°)
34 – Javier Baez (9.2°)
34 – Eugenio Suarez (14.7°)
34 – Rhys Hoskins (22.4°)
33 – Paul Goldschmidt (15.7°)

The reason why Yelich was able to hit a lot of home runs despite his low launch angle is his elite exit velocity and his 35.0% HR/FB ratio. Essentially, every three fly balls he hit resulted in a home run. This is by far the best in the majors this year, nearly three times the league average 12.7% (2017 Yelich 15.3%). Moreover, Yelich’s HR/FB ratio this year is the third highest ever since the stat was recorded in 2002, only trailing 2006 Ryan Howard (39.5%) and 2017 Aaron Judge (35.6%).

The problem is, such a high HR/FB ratio is difficult to maintain. For example, Shawn Green hit 42 home runs in 2002 with a 29.8% HR/FB ratio, but only hit 19 home runs a year later, when his HR/FB ratio decreased to 11.9%. Do keep in mind that 2003 was Green’s age 30 season; Yelich is turning 27 next year. In other words, if Yelich manages to increase his launch angle and continues to do everything else as he’s done this year, it will be no surprise that he can become an even better hitter for years to come.

(Edit: One might question how Yelich is enjoying continued success following his MVP campaign despite my analysis here. As of June 19, 2019, Yelich’s average launch angle for the season is 12.2º, a massive increase from his 4.7º in 2018 and slightly above league average.)

Mookie Betts. J.D. Martinez. And Christian Yelich. It is exciting to see how these elite hitters will perform in 2019. By analyzing their approaches to hitting, we will be able to identify the trends of hitting in the MLB.

Unless otherwise noted, all statistics are from Baseball Reference, FanGraphs, and/or Baseball Savant.