Case Study: NPB to MLB

A case study on the transition from the Japanese baseball league to the Majors, and what we can expect from Seiya Suzuki. 

Japanese baseball star Seiya Suzuki has announced that after 9 seasons in the NPB, the top flight of baseball in Japan, he will be taking his talents overseas to the Major Leagues. Given his high production levels in Japan, he has garnered the attention of many MLB teams. 

While Suzuki may bring an impressive resume to the United States, MLB is considered the highest level of baseball for a reason. So, what can we really expect out of him in 2022? 

With this analysis, I will present projections for Suzuki's 2022 MLB season to try to add some context to his value. I created models by analyzing previous Japanese players that made the switch to the MLB, and finding how their stats were affected as they got acclimated to the American game. 

I then found a couple players that had similar numbers in 2021 to Suzuki's projections to give a ballpark (no pun intended) estimate for the annual value of his potential contract.

Since the implementation of the posting system allowing NPB players to go to the Major Leagues in 1999, there have only been a handful of Japanese players to make the switch. Out of this handful, only 6 players reached at least 300 At-Bats in the MLB. This is a deep dive into how these players fared in their transition. 

I chose to analyze the 4 most common statistical averages used when evaluating a players offensive ability: Batting Average (BA), On Base Percentage (OBP), Slugging Average (SLG), On Base Plus Slugging (OPS). For reference, in the 2021 MLB season, the league averages for these statistics were: 

.244/.317/.411/.728

Statistical Difference from the NPB to MLB

The box and whisker plot above shows how players stats were affected during their transition to the MLB. By hovering over the plot, you can see how an individual stat was affected for each player. This gives us a framework for projecting Seiya Suzuki's numbers for the 2022 season. 

Projecting Seiya Suzuki's 2022 MLB Season

The table above shows Suzukis potential slash lines if he were to have a similar transition to each of the 6 Japanese players preceding him. The projections are made using Suzuki's stats from 2019 to 2021 in the NPB. At the bottom of the table, we see first and third quartile projections, as well as an aggregate average of the 6 player projections. 

Now that we have some concrete projections, we can look for 2021 MLB seasons that resemble these numbers. The following is a list of players whose slash lines fall between the boundaries set by our projections. 

Player	AVG	OBP	SLG	OPS	AGE
C.J. Cron	0.281	0.375	0.53	0.905	32
Matt Olson	0.271	0.371	0.54	0.911	27
Mookie Betts	0.264	0.367	0.487	0.854	29
Carlos Correa	0.279	0.366	0.485	0.85	27
Jonathan India	0.269	0.376	0.459	0.835	25
Justin Turner	0.278	0.361	0.471	0.832	37

A green cell represents a value that exceeds our models expectations for Suzukis 2022 season, while red cells denote values that are less than we project for Suzuki. 

Now, what does it mean for Seiya to be grouped with this collection of players? 

Well, of the 6 seasons summarized in the table above, 4 of them resulted in All-Star selections, as well as Jonathan India winning Rookie of the Year in 2021. 

Not bad company!

By analyzing the contracts of the player comps, I would expect Seiya Suzuki to command a contract in the annual range of $13-19 million. While this may seem like a large range, this is an estimate made purely on the offensive output of the player, without taking in to account their position or defensive attributes. 

Update: On March 17th, Suzuki signed a 5-year, $85 million contract with the Chicago Cubs. At $17 million per year, his contract falls in line with my prediction. 

Programs Used

• Data downloaded from online database 
• Data analysis and manipulation done on Microsoft Excel
• Data visualization done on Tableau

References

1. Players statistics were taken from the Baseball Reference Archives.

2. Filtered through 2021 seasons with Fangraphs Advanced advanced stats to find relevant player comps

https://www.baseball-reference.com/players/