Why players from the KBO are misunderstood

 

English audio above. Korean audio below.

Hye Seong Kim's start in his MLB career didn’t work out as well as expected, but to judge him through 31 plate appearances is not fair. The reason is that they tried to alter his swing too much to the point that instant adjustment is almost impossible. 

His swing was a habit that he developed, and he became an elite hitter in the KBO. When something is not broken, don’t fix it. Before preseason even began, the Dodgers already tried to change him as a player by altering his swing. I contend that altering his swing disrupted his rhythm, causing him to struggle and strike out 10 times in 31 at-bats. By changing his swing, there was no leeway to adjust at all.

In contrast, the Giants allowed Lee Jung Hoo to thrive independently, making minimal or no adjustments to his swing. The Giants trusted him, and as a result, he flourished in the 2024 preseason. Although he experienced a brief slowdown during the regular season, he gradually adjusted by hitting over .310 in his last 7 games. He collected 9 hits, an RBI, and scored 2 runs, which increased his batting average to .262 for his shortened 2024 season. So far in the 2025 preseason, he is hitting .333, hitting 2 homers with an OPS of 1.067. He is poised, according to many predictors, to have an excellent 2025 season. 

I wouldn’t be too concerned whether Hye-Seong can make the big league club or not. He eventually will. It's unclear when he will receive a call-up, but the season is long. It could happen at any time. With the new swing, he couldn’t seem to adjust instantaneously like they wanted, so they elected to start his season in Triple-A; however, the move was a premature decision at best. What they should have done is let him get as many at-bats as possible, not bench him when he struggled with 15 at-bats. With just 9 at-bats, they were already counting him out. Then, they benched him, only getting 1 at-bat in some games. It’s spring training. You let him play. It’s not like the postseason or anything. No one ever subjected Lee Jung Hoo to such scrutiny. The Giants let him roam around freely, and, in turn, he grew and adjusted on his own. 

There’s this notion of belief that KBO hitters never play out. There are not enough examples of players moving from KBO to MLB to support that assumption. How many KBO players made the leap to MLB? Shin-Soo Choo? However, Shin-Soo Choo didn’t play professional baseball in the KBO before joining MLB. He was practically a US product. He was a product of hard work and dedication, along with the support of the Seattle Mariners organization, the team in which he eventually made his pro debut in 2005. Yes, he did play in the KBO, but he made his debut in Korea in the KBO in 2021, the waning years of his career.

There is only a handful of KBO players who went to MLB. There’s Jae-Gyun Hwang, who played briefly for the San Francisco Giants. He’s easy to forget. We will delve deeper into him in the future. There’s Hee-Seop Choi, but he can’t be counted as a KBO product either because, like Shin-Soo Choo, he didn’t start his career in the KBO. He was a major league product, but unlike Choo, his MLB career was not successful. He would eventually play in the KBO, but only after his career in the MLB ended in 2005. Two years later, he made his debut in the KBO in 2007, a career that proved successful, averaging .291 in his career there.

Of the former Korean players who played for an MLB team, only 7 of them were position players, 5 of whom began their professional careers in the KBO.

Here are some names:

Byung-Ho Park. KBO debut: April 2, 2005. MLB debut: April 4, 2016. He played in MLB so briefly that it's easy to forget about him. 

Dae-Ho Lee. KBO debut: September 19, 2001. MLB debut: April 4, 2016. He had a brief stint as a player for the Seattle Mariners.

Hyun-Soo Kim. KBO debut: September 2, 2006. MLB debut: April 10, 2016. He played for the Baltimore Orioles from 2016 to 2017, followed by the Philadelphia Phillies in 2017, before making his return to the KBO.

Jung-Hoo Kang. KBO debut: April 8, 2005. MLB debut: April 8, 2015. He spent four years playing in the major leagues for the Pittsburgh Pirates. 

Jae-Gyun Hwang. KBO debut: April 21, 2007. MLB debut: June 28, 2017, for the San Francisco Giants.

Of the current MLB players of Korean descent, only 3 actually played in the KBO.

Ha-Seong Kim, Jung Hoo Lee, and Hye-Seong Kim are the only ones who were stars in the KBO. We know that Ha-Seong Kim and Jung Hoo Lee can hit MLB pitching. They are not the best hitters in the league, but they can at least hit MLB pitching better than the league average. Ha-Seong even won a Gold Glove in 2023, besting even Juan Soto in WAR value when they were teammates for a year.

There are other players of Korean descent, but they cannot be considered part of the list because they didn't begin their careers in the KBO. These players are Ji-Hwan Bae (forgoing the KBO draft), Ji-Man Choi (currently playing for the Syracuse Mets), Rob Refsnyder, and Hoy Park (currently an infielder for the Gwinnett Stripers).

Hye-Seong Kim will eventually get comfortable. When he does, he will eventually lead the Dodgers to another championship.

In conclusion, there’s a lack of examples to know if a hitter from the KBO will or will not adjust to MLB pitching. While there’s a difference on average in velocity between the two leagues, there are also some pretty hard throwers in the KBO. 

Velocity in the KBO has risen from 85 mph to 90 mph, with some younger generations touching as fast as 98.7 mph. There’s about a 4-5 mph difference on average between the KBO and MLB, with some variations or some KBO pitchers capable of throwing MLB velocities. The KBO has more room for velocity growth, as it will become increasingly difficult for MLB fastball velocity to increase further without causing serious injuries to pitchers' arms. 

Throughout MLB history, there have only been 8 position players of Korean descent to have started their careers in the KBO before moving to MLB, 5 of whom were already in the waning stage of their professional careers. And, of all 8 players, only 3 were 26 years of age or younger. They are Ha-Seong Kim, Lee Jung Hoo, and notably Hye-Seong Kim, who will be starting his US baseball career in Triple-A.