Juiced Baseballs? – Blog Post 3


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Probably the most exciting play in baseball. The home run. The play that gets the crowd wild. Is major league baseball deliberately increasing home runs to increase excitement during games? Probably not. This is an important matter because many people are affected by this. First, the pitchers. The one giving up those home runs. An increase in home runs could lead to an increase in the average number of runs a pitcher gives up per game. Declining performances by pitchers will affect their salaries and bonuses. Second, teams that are pitching-oriented. There are certain teams that build their teams to have good pitching and some that build their team around good hitting. The New York Yankees, the “Bronx Bombers”, are a team that has really good offensive players, compared to the New York Mets who have a really good pitching staff. Third, gamblers. sports betting has become a multi-billion dollar industry. If major league baseball is implementing radical changes to the game, then the people should be aware of those changes to give them a fair shot at betting.

Pitchers are alleging that this year, the baseballs are “carrying” more. Meaning they are traveling in the air for longer periods of time, leading to an increased number of home runs. However, from the chart above, we see that home runs have been increasing since 1920. We see some dips during some years but the trend is that they have been increasing. The increase in previous years is due to the number of games per season increasing, along with the number of teams almost doubling since 1920. We should wait to see if this trend continues or if home runs decrease, meaning 2019 had an unusually high number of home runs.

From the table above, we see that the home run leaders for 2019 did not have an unusually high number of home runs, compared to other years. The only numbers that jump out at us are the years 1998, 1999, and 2001 for the National League. Those numbers were put up by Mark Mcgwire and Barry Bonds, players that were accused of using performance enhancing drugs. Also, for the American League, Alex Rodriguez led the American League in home runs for 5 years. He was suspended for the entire 2014 season after testing positive for performance enhancing drugs and admitted to using the ped’s from 2001 to 2003.

Baseball fans and enthusiasts already know that home runs are associated with strikeouts. However, this correlation shows how big the relationship is. For the year 2019, we see a huge amount of home runs, but also strikeouts. While these numbers are large compared to other years, we still see the relationship between home runs and strikeouts. If home runs were had increased due to altered baseball, then we shouldn’t see an increase in strikeouts, yet we do.

Offensive Runs Above Average. A new statistic created in recent years to summarize a players offensive contribution to their team. It’s basically how many more runs a player contributes to his team, compared to an average, generic player. During recent years, players are being judged in these new, more advanced ┬áset of statistics, rather than using common ones such as batting average, runs batted in, on-base percentage. Here we see how home runs have a stronger relationship compared to non-home run hits (singles, doubles, and triples).

I then decided to run a Mantel-Haenszel Test of Trend to see if there is a relationship between the number of home runs and a players offensive runs above average score. The results showed that there is a significant linear relationship between the two variables. Players that have a higher home run count, have a higher offensive runs above average score. From the bar chart we see that 53.7% of players who hit 41 or more home runs had an offensive RAA score of 41 and higher. This shows that teams may be training their players to hit more home runs, in order for them to have a more valuable contribution to their team.

I decided to look at Brett Gardner’s stats from 2018 and 2019. He is a player that has always been known for his speed and ability to get on base. He was once one of the fastest guys in the league, during his younger years. His 2018 season was not good. His production was very low and the team and fans were questioning wether he should be on the team for next year. However, they were glad he came back for next year. His production numbers skyrocketed in 2019, specially increasing in home runs and offensive runs above average. Many used him as an example as to how the baseballs were being juiced. How did an aging player increase his home run totals from one year to the other? From the bar chart above we see an increase in home runs, strikeout percentage, swing %, and launch angle. Most power hitters have a higher value of those stats compared to contact hitters. We also saw a decrease in the number of singles and contact %, stats that signal a contact hitter. I believe that Brett Gardner switched his approach from being a contact hitter to being a power hitter. So far it has paid off really well. He increased his offensive runs above average score by almost 500% from 2018 to 2019. It would be interesting to see if he can recreate these number for next season.