'Wa' KIA 5R sidearm, ERA 0.90 one year after elbow surgery... How was it possible to grow explosively by shortening rehabilitation by three months? [Interview]

*This content was translated by AI.

KIA Tigers left-handed sidearm Kwak Do-gyu (22) revealed the secret to overcoming his difficult elbow surgery rehabilitation.

On the 21st, Kwak Do-gyu appeared as the third pitcher in the regular-season match between KT Wiz and the visiting team at Suwon KT Wiz Park in the 2026 Shinhan SOL KBO League, pitching a perfect inning by recording just one strikeout.

He did not yield at all against KT's top batting order featuring Choi Won-jun, Ahn In-san, and Ahn Hyeon-min. He did not hesitate to throw inside to Choi Won-jun, who is recording the highest batting average in the league, and eventually induced a ground ball to second base. Against Ahn In-san, whose strength is power hitting, he instead threw hard, fast pitches right into the strike zone, forcing a swinging strikeout.

The showdown with Ahn Hyeon-min, a right-handed batter who combines the strengths of both Choi Won-jun and Ahn In-san, was the highlight. The first three pitches were far outside the strike zone, putting him in an unfavorable count. However, he followed up with a two-seam fastball and a cutter right down the middle, causing confusion, then induced a ground ball to the shortstop with a two-seam fastball that dropped low on the outside.

As a result, Kwak Do-gyu achieved 10 consecutive scoreless innings, bringing his ERA down to the 0th-point range. In 15 games, he has recorded 1 win, no losses, 4 holds, an ERA of 0.90, 10 innings pitched, 6 walks, and 9 strikeouts, delivering top-tier league performance. After the game, Lee Beom-ho, KIA General Manager, specifically praised him, saying, "Kwak Do-gyu cleanly held the line for one inning again today (21st). As the games progress, he is showing increasing stability."

Just a year ago, such a scene would have been hard to imagine. Kwak Do-gyu suffered a tear in the flexor muscles and ligaments of his left elbow last May and underwent elbow ligament reconstruction surgery (Tommy John surgery). About a year and three months of rehabilitation was expected, and since this was a period of absence at a time when he was just beginning to understand baseball, there were concerns that he might lose his feel.

However, his performance has dispelled public concerns. Instead, he is showing performance comparable to a closer with even faster velocity and more skilled game management. Kwak Do-gyu's two-seam fastball velocity has increased from an average of 142.6 km/h last year to 145.2 km/h this year. We were able to hear the secret behind this during an interview with him before the match on the 21st.

Meeting with StarNews in Suwon, Kwak Do-gyu said, "My rehabilitation period was 2-3 months shorter than others. To shorten that rehabilitation period, I chose to have surgery in Japan. Also, it was effective that I never missed a single day of the step-by-step throwing program (ITP·Interval Throwing Program) provided by the team. As long as there was no pain in my arm, I went to Hampyeong on the scheduled dates even in winter to play catch or performed the ITP schedule with friends in the park."

He continued, "I also wanted to share the good points from this rehabilitation with my friends, so after finishing, I pondered what was different. The result was that I did not engage in what are commonly called occupational habits of baseball players, such as shadow pitching in front of a mirror. I focused only on throwing motions according to the set ITP schedule and acted like someone with no interest in baseball at all during other times. Even though I worked hard on weight training during other times, I did not perform any throwing motions to find a light rhythm."

In the baseball world, Kwak Do-gyu is seen as a typical young player who constantly thinks and studies. During the championship season, news spread that he read books every day, giving him an academic image. However, Kwak Do-gyu clearly drew a line on this point.

Kwak Do-gyu stated, "It seems I have developed an image of reading a lot of books, but that is not the case. I simply read one page of a book related to baseball psychology before each game every day. I am grateful that reporters wrote about me in a positive light, but it is not true."

However, seeing his efforts to improve even from slightly unfavorable results makes the misunderstanding of him being academic seem natural. This year, Kwak Do-gyu has been gradually lowering the batting average against left-handed batters by increasing his usage of the cutter, a pitch he had not thrown much before. Behind this was significant concern about the curveball he has recently been using.

Kwak Do-gyu explained, "The curveball is really good according to the data. The coaches also say it's good, but recently there have been a few hits that were well-struck. As a result, my confidence dropped a bit. Also, recently there have been many situations where I absolutely cannot give up a solid hit. I have confidence in throwing the cutter, so its usage has increased recently. Still, I do not see a huge difference between the cutter and the curveball."

A representative example was the RBI hit by Hong Chang-ki in the May 31 match against Jamsil LG Twins. At that time, Kwak Do-gyu appeared in the bottom of the 6th inning with the score tied 2-2 and two outs with a runner on first base, allowing consecutive RBI hits to Hong Chang-ki and Park Hae-min, providing the opportunity for defeat. It is said that he was quite heartbroken even though it was an unlucky hit.

Lee Dong-keol (43), KIA 1st Division Pitching Coach, explained, "When (Kwak) Do-gyu first came up to the 1st division, he used a lot of curveballs and two-seam fastballs against left-handed batters. However, the batting average against left-handed batters was a bit higher than expected. It was not strong hits, but rather hits that were unlucky and beyond our control, which made Do-gyu worry."

He continued, "Since it is the first season after rehabilitation, he says there are parts where the movement of breaking balls does not come out as he thought. It should have resulted in a swinging strikeout on the curveball, but contact was made first. He is originally a pitcher who knows how to throw a cutter. In 2024, he used the cutter, but as the curveball's completion improved, he reduced the cutter, and now he has just switched the order of usage. By separating the pitches a bit like that, good results followed."

Despite just bad luck, his repeated thinking and changes have made him a nightmare even for top-tier league batters. On June 8 against Choi Hyung-woo in the Gwangju Samsung match and on the 18th against Moon Bo-kyung in the Gwangju LG match, both ground balls were recorded with the cutter. This aspect of Kwak Do-gyu's performance made explosive growth possible despite a one-year absence.

Kwak Do-gyu said, "I blamed myself that the curveball touched the bat even in situations where it could have been caught even if it wasn't a solid hit. I regretted choosing that pitch." He added, "I always try to have confidence, even if it is fake. That is my mission, so I will do it for sure. Now that I have gained confidence in facing right-handed batters as well, I want to take responsibility and finish the inning no matter the situation."

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*This content was translated by AI.