MLB 2018 Season — A Visual Review

Published in

Sports Analytics

3 min readOct 2, 2018

It has been a great year for the MLB. The Yankees broke the record with the most team home-runs in one season (267) and the Red Sox had the most wins in the franchise history (108). The A’s set an attendance record for the Coliseum earlier this year (56,310) and Tyler White (Houston Astros) had the pleasure to hit the 81st walk-off home-run this season, setting a season record for the major league. On a less-optimistic note, more than $700 million was spent on players on Disable List (DL) this season. From a data perspective, Statcast introduced three new metrics for the sabermetrics fans: pop time, exchange time and arm strength, continuing to add excitement to the data geeks in the industry. But as pictures are worth a thousand words, let us get to a summary of the MLB 2018 Regular Season, in charts.

Home Runs

There were 5,580 home runs this season, a slight decrease from the 6,105 in 2017 and 5,610 in 2016. Even so, the Yankees were able to push the record to season-wide home runs for one team to 267 HR last weekend. Let’s see if those numbers translate into playoff performance.

Strikeouts

Are strikeouts still on the rise (as they used to be)? You bet. This might even be a consequence of data-driven decisions and the impact of analytics on baseball (more on it here). What is more concerning is how strikeout averages have risen year after year, making baseball potentially more strategic and less watchable.

Hit Probability: Launch Angle vs. Exit Velocity

Guess what? Launch angles continued to increase this past season. As the focus on higher angles remains, overall average angle for any batted ball was 16.02*, compared to 15.88 in 2017 and 15.56 in 2016. It feels that the pursuit of the optimal angles remain in the head of hitters as a key component driving better performance. It is interesting to see how both batters and pitchers are constantly reacting to the information they now have available

Hit Probability 2018. Data Source: Baseball Savant

Defensive Power

When we look at the impact of outs above average (the number of outs made vs. the ones expected to happen given the difficulty of the catches) and the average strikeouts by pitcher, we are better equipped to see what is ahead of us in the playoffs. The Astros have 17 outs above average, with an average of 10.38 strikeouts per game by pitchers. While the Dodgers and Red Sox have great teams, it seems that Houston is keeping a better balance between offensive and defensive power.

OOA and Strikeouts by pitchers. Source: Baseball Savant

Pitches Distribution and Location

Well, it should not be a surprise that fastballs remain the weapon of choice among pitchers. Precisely, it is used around three times more than Sliders, and Change-Ups this year.

Pitches by type. Source: Baseball Savant

Pitch locations (x and z) based on pitch type. Source: Baseball Savant

Notes

*Launch angle and exit velocity per Sep 26,2018.
Data sources: Baseball Savant and Baseball Reference
For a detailed explanation on Outs Above Average, check the Statcast explanation.
For great insights on hit probability as a function of launch angle and exit speed, check this by FiveThirtyEight and The Washington Post
Data processed in Python and visualizations in D3.js