Kim Seo-hyun (19‧ Hanwha), a ‘special rookie’ who shines first overall in the 2023 rookie draft, surprised many people at the Jamsil Doosan match held on the 3rd. The pitching form has changed. It was a change that even Hanwha coach Carlos Subero did not seem to be aware of.
Technically, Seohyun Kim is close to the three-quarter style. He has a higher arm than a sidearm and a lower arm than an overhand. But on this day, his arm height went up. He also lost the movement of hitting the glove before pitching. Considering that the previous appearance was on April 30, the pitching form has changed and appeared in just a few days. Kim Seo-hyun was doing things that other people would have to spend a season with, so calmly.
If you look at the tracking of ‘Trackman’, which provides tracking data to 9 KBO league teams, this change is revealed very clearly. At the time of his first appearance, against Doosan in Daejeon on April 19, Kim Seo-hyun’s fastball release point was 148 cm. This is not much different from Kim Seo-hyun’s measurement at the time of the demonstration game. The vertical movement was 24.3 cm and the horizontal movement was 44.3 cm, so the horizontal movement was much larger.
However, at the time of the match against Doosan in Jamsil on May 3, Seohyun Kim’s fastball release point rose to 161cm. Even a change of 3 to 4 cm is a big change, and compared to the first appearance, it is a whopping 13 cm. The feelings experienced by many people were revealed in the record. While the vertical movement increased to 37.9 cm as the arm was raised, the horizontal movement slightly decreased to 36.2 cm. Instead, the number of revolutions per minute (RPM) increased slightly, and the average velocity fell slightly instead.
While the change in pitching form was a hot topic, in fact, looking at the tracking data, Seohyun Kim’s release point was gradually increasing. Compared to his release point at the time of his first appearance, which was 148 cm, the average of 5 matches by the end of April was 158 cm, which symbolizes gay. And Kim Seo-hyun surprised everyone again in the next appearance. In the game against kt in Daejeon on May 7, the arm height went down a little again. Perhaps it can be seen that he returned to his pitching form before the match against Doosan on the 3rd.
The redemption also went up again. The average speed of the fastball on this day was 155 km per hour, much better than the Doosan match (152.3 km). It is generally known that a three quarterer can release a ball more comfortably than an overhand, but this is also the case in Seohyun Kim’s case. The horizontal movement has returned with better characteristics than the vertical movement. However, it is more frightening to prove that you can throw by changing styles at any time.
When a rookie debuts on the professional stage, it is usually difficult to look left and right. In a tense stage, under pressure to do well, it is natural to go straight with only what you have. However, Seohyun Kim has enough time to set up a ‘laboratory’ during the season. He is Kim Seo-hyun, who says that he did not hesitate to experiment with various things even when he was in high school. One commentator said, “It seems to be looking at the reaction of opponents. “The patience of the Hanwha coaching staff is also interesting,” he said.
In the meantime, he is steadily settling down on the stage of the 1st team while maintaining his grades to some extent. Kim Seo-hyun is recording an average ERA of 3.38 by throwing 8 innings in 7 games of the season. His batting average is only 0.185. This is a decisive proof that the opposing hitters are having a hard time targeting Kim Seo-hyun’s fastball. The anxiety of the jegu that I was worried about is not that big so far. While he struck out 10, he gave up 3 walks. You will have to keep coming up with commands, but the strikeout/walk ratio, which is a pitcher’s unique indicator, is not bad. 안전놀이터
Kim Seo-hyun throws a fastball with an average speed of 155 km (according to Trackman), and her curveball, which is also classified as a slider, is showing great power. Kim Seo-hyun’s curve batting speed stays at an average of 120.6 km. This year, only 20% of players hit Seohyun Kim’s curve and recorded a batting speed of 145 km or more. The contact rate is also efficient, below 70%. A fastball with a lot of movement often induces a ground ball.
It won’t be easy to become a reliever pitcher who dominates the league from the start. First-team hitters are obviously not easy. However, if Kim Seo-hyun can minimize trial and error through various experiments and quickly create an optimal pitching style, it is not easy to gauge the end of this enormous potential. Sometimes we are nervous, but that is also why Seohyun Kim’s ‘Laboratory’ catches our eyes.