I hope you're different… Jangchung High School Seo Moon-joon officially joined MLB Toronto. The Odds of Success in the Worst High School Prospects, Will It Be able to Break through the 0% Wall

Sep 25, 2025

Seo Moon-joon is smiling brightly while wearing his uniform after signing a contract with the Toronto Blue Jays in Major League Baseball at the Toronto Rogers Center in Canada on the 25th (Korea time). Photo courtesy = Rico Sports Agency

"We will not be afraid of failure and grow one step at a time."

Jangchung High School senior Seo Moon-joon, who threw a 155km/h fastball in excellent physical conditions and was evaluated as a 'large pitching prospect', joined the Toronto Blue Jays in the Major League Baseball (MLB). Seo Moon-joon expressed his bold and realistic ambition to join the team. As Seo Moon-joon said, you can grow when you are not afraid of failure, and the more you do, the closer you are to success.

However, there is no guarantee that this will succeed. This is because the probability of success is so heinous. Over the past 20 years, none of the high school graduates who have challenged the MLB stage with the evaluation of being similar or better than Moon Jae-joon have successfully made their careers so far. It is an extremely difficult challenge of '0% success probability'. Attention is focusing on whether Moon Jae-jun can break the wall of '0%'.

This season, Seo Moon-joon, one of the "high school's biggest words" signed an official contract with the Toronto club and even held an official joining ceremony at the Rogers Center in Toronto, Canada. The Toronto club gave a positive evaluation of Seo Do-jun as a prospect with physical conditions and various breaking balls suitable to grow into a starting pitcher in the Major League. The down payment is worth a whopping 1.5 million dollars (about 2.1 billion won). Toronto has considerable expectations for Seo Do-jun.

Photo provided = Rico Sports Agency

Rico Sports Agency, which is in charge of Seo Do-jun's agent, announced on the morning of the 25th (Korea time) that Seo Do-jun signed a formal contract in Toronto on the afternoon of the 24th local time and completed the official joining process at the Toronto Rogers Center.

As a result, Seo Moon-joon became the second high school player to pass the KBO draft and sign a contract with the MLB club after Kim Sung-joon (Gwangju Il High School) this year. Kim Sung-joon signed a $1.2 million (about 1.68 billion won) contract with the Texas Rangers in May.

Seo Moon-joon was considered the highest-level prospect among high school third-year pitchers this year and was expected to be a strong first-round KBO draft nominee. Above all, the excellent physical condition and fastball stand out. It is a height of 1m96 and is 'post-Asian class'. It is bigger than LA Dodgers Shohei Ohtani (1m93). Of course, height does not guarantee major league success.

Starting with a 155km fastball, it is equipped with a variety of repertoires such as two-seam, slider, curve, and change-up. His ball control is also at the top of the list at the high school level in Korea. Seo Moon-joon pitched in a total of 24 high school baseball games and recorded a 2.18 ERA and 93 strikeouts in 66 innings.

Docjun (center), who signed with the Toronto Blue Jays, greets Toronto manager John Schneider at the Toronto Rogers Center. Photo courtesy = Rico Sports Agency

What is noteworthy is that he has not allowed a single home run in 66 innings. Daejin luck may have been good, but once you look at the record, it seems that he has a strong ball power. However, it is unclear whether this ball will work for minor league and major league hitters who have different power from domestic high school students. This is also one of the homework that Seo Moon-joon has to overcome.

Andrew Tinish, vice president of international scouting and baseball operations in Toronto, said, `"Jo Moon-jun is a promising player with physical conditions and various breaking balls suitable to grow into a starting pitcher in the Major League Baseball. Our club will provide an optimal growth environment and we look forward to establishing ourselves as a recognized pitcher by fans in Korea and around the world through steady efforts."

"It is an honor to be able to challenge for the best club in the Toronto Blue Jays on the major league stage that I have dreamed of since I was young," Seo said through the agency. "We will grow step by step without fear of failure." I sincerely thank my family and leaders for trusting and supporting me" expressed his feelings.

At Rogers Center, Seo Moon-joon smiled brightly wearing a uniform with his number 45 engraved on it. But it's just a joining ceremony. Real difficulties are coming up in the future. It can be said that it is a real success only when it exceeds this.

The problem is that the probability of success is 'Extreme'. In fact, so far, no pitcher has graduated from high school and tried MLB, but succeeded. The probability of success is '0%'.

Until last year, a total of 57 players, including pitchers and fielders, signed with a major league club in high school and moved to the U.S. with graduation. Among them, a total of seven players went up to the MLB stage. Four were fielders (Chushinsu Choi Ji-man, Park Hyo-joon, Bae Ji-hwan), and three were pitchers (Baek Cha-seung, Bong Jung-geun, Ryu Je-guk).

However, Baek Cha-seung, Bong Jung-geun, and Ryu Je-guk's MLB careers are far from objectively 'success'.

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Baek appeared in 59 games in a total of four seasons for the Seattle Mariners (2004, 2006-2008) and San Diego Padres (2008), throwing 279 ⅔ innings with a 16-18 record and 4.83 ERA, before facing a 'release ending'. It is the only case that has surpassed 10 Tongsan.

Bong Jung-geun played 78 ⅓ in a total of three seasons for the Atlanta Braves (2002-2003) and Cincinnati Reds (2004), leaving a career-high 7-4 with one save and two holds and a 5.17 ERA. Ryu Je-guk also returned to Korea after recording just one win (three losses) with a 7.49 ERA in just three seasons (2006-2008).

Unlike their short MLB careers, they had to challenge themselves on the minor league stage for a long time. Baek Cha-seung and Bong Jung-geun spent as many as nine years in the minor leagues, and Ryu Je-guk played for eight seasons. Compared to the time of hard work, the results were insignificant.

Ryu Je-guk, who was considered an ultra-high school pitcher in his junior year of Deoksu, signed with the Chicago Cubs. Sports Chosun DB

At least these three are seniors who have eaten so-called 'major league water'. Dozens of other `high school top prospects' disappeared in silence. They were once the most praised and expected stars, but now they remain unknown.

In the end, both Moon Jae-joon and Kim Sung-joon took on very difficult challenges. But this is also your choice. As Moon Jae-jun aspires, you can grow steadily and break the wall of '0%' without fear of failure. I sincerely hope that among Seo Moon-joon and Kim Sung-jun, the first MLB pitcher to succeed as a high school graduate in Korea will be born.

This article was translated by Naver AI translator.