Naoyuki Uwasawa

1.1. Childhood and High School Career

Uwasawa was born in Matsudo, Chiba, Japan. In his early childhood, he was actively involved in soccer. He later joined the baseball club upon entering Matsudo Municipal First Junior High School, though the team was not particularly strong, and he remained a relatively unknown player nationally.

Upon entering Senshu University Matsudo High School, Uwasawa secured a spot on the varsity roster from his first year. By his second year, he emerged as the team's ace. In the spring Kanto Regional High School Baseball Tournament, he faced Tokai University Ichihara Boyo High School, a team that had participated in the Spring Koshien Tournament. Uwasawa delivered a strong performance, pitching seven innings with 12 strikeouts and allowing no runs, leading his team to a mercy-rule victory. The team subsequently advanced to the best eight, drawing attention to Senshu Matsudo's overall strength in both pitching and hitting. In the summer of his second year, the team reached the prefectural best four, though they did not qualify for Koshien. In the autumn of his second year, they again made it to the prefectural best four. In the spring of his third year, Senshu Matsudo High School finished as runner-up in the Chiba Prefectural Tournament, earning a spot in the Kanto Tournament for the first time in 12 years. Although the school had previously lost in the first round twice, Uwasawa started their opening game against Maebashi Commercial High School, pitching a complete game with nine innings, three hits, eight strikeouts, and one run, securing the school's first victory in the tournament. In the summer of his third year, during the Chiba Prefectural Tournament, he faced Kohei Suzuki of Chiba Meitoku High School in the second round, recording 16 strikeouts in a game that ended in an 11-inning draw due to tournament rules. In the following day's rematch, he entered the game in the sixth inning with a lead and held the opponent scoreless, contributing to a 5-2 victory. However, in the fourth round, he started against Tokyo Gakkan Urayasu High School, pitching six innings and allowing three runs, taking the loss and failing to reach Koshien.

1.2. Draft and Professional Signing

On October 27, 2011, Uwasawa was selected by the Hokkaido Nippon-Ham Fighters in the sixth round of the 2011 NPB Draft. On November 9, 2011, he provisionally signed with the Fighters for an estimated signing bonus of 20.00 M JPY and an annual salary of 4.80 M JPY. His official signing ceremony took place on December 3, 2011, where his uniform number was announced as 63. His scout was Yasuaki Imanari.

2.1. Early Years and Development

In his rookie year of 2012, Uwasawa focused on physical development. He appeared in 10 games in the Eastern League (minor league), pitching 27.2 innings with a record of 0 wins and 4 losses, and an ERA of 5.20. In 2013, he was selected for the Fresh All-Star Game. Initially scheduled as the second pitcher after Yudai Mori (Rakuten), he was unexpectedly named the starter after Mori withdrew due to a lower back injury. Uwasawa pitched two innings, allowing no hits and striking out two batters without giving up a run, earning the Excellent Player Award. Although he did not make a first-team appearance that year, he pitched 107.1 innings in 18 Eastern League games, recording 4 wins, 8 losses, and an ERA of 4.95.

In 2014, Uwasawa participated in the first-team spring training for the first time. He was given a starting role in the initial Red-White game on February 6 and continued to impress throughout the preseason, earning a spot in the opening day starting rotation. On April 2, in the fourth game of the regular season against the Fukuoka SoftBank Hawks, he made his professional debut as a starter, pitching six innings, allowing three hits and one run while striking out seven, to earn his first professional win. This marked the first time a Nippon-Ham pitcher recorded a win in his first professional appearance since Yuki Saito (2011), and the first for a high school pitcher since Masaru Nakamura (2010). On April 9, against the Tohoku Rakuten Golden Eagles, he secured his second win and first home win at Sapporo Dome, pitching into the sixth inning and allowing two runs. On April 16, against the Orix Buffaloes, he earned his third win, pitching seven innings and allowing three runs. This made him the first Japanese pitcher for the team in 52 years, since Yukio Ozaki in 1962, to achieve three wins in his first three professional starts. Although he struggled to secure wins after June, on September 15, against the Orix Buffaloes, he pitched a nine-inning, three-hit, two-walk, six-strikeout, no-run gem, recording his first professional complete game and shutout. He established himself in the starting rotation that year, finishing with 8 wins and 8 losses and an ERA of 3.19 in 23 appearances (22 starts), narrowly missing the innings pitched qualification. He also started in Game 2 of the First Stage and Game 6 of the Final Stage in the 2014 Pacific League Climax Series. In November, after the season, he was selected to the Japan national baseball team for the 1st 2014 WBSC U-21 Baseball World Cup. He pitched effectively in two starts, totaling 12 innings, allowing nine hits and one run while striking out 21, and was named to the tournament's Best Nine as a starting pitcher. Following the season, his contract was renewed for an estimated 23.00 M JPY, an increase of 18.00 M JPY.

2.2. Ascent to Ace and Key Achievements

Uwasawa's true ascent to an ace pitcher began in 2018. After more than two years of trial and error following his right elbow injury, he found a pitching form that suited him. Additionally, he added a knuckle curve to his repertoire, which significantly contributed to his breakthrough. He secured a spot in the opening day rotation and on May 16, he pitched his first shutout in four years against the Seibu Lions. On May 23, against the Chiba Lotte Marines, he pitched eight scoreless innings, which was recorded as his second consecutive shutout due to a rain-shortened game. On June 26, he achieved his third shutout of the year against the SoftBank Hawks, doing so without issuing a walk. By July, he had an impressive 7-win, 2.04 ERA record, earning his first selection to the 2018 NPB All-Star Series. That year, he started 25 games, recording 11 wins and 6 losses, with 4 complete games (tied for 2nd in the Pacific League), 3 shutouts (1st in the league), and 165.1 innings pitched (3rd in the league), with an ERA of 3.16 (3rd in the league). He maintained his position in the starting rotation throughout the year, earning recognition as the team's ace. After the season, he was selected for the 2018 MLB Japan All-Star Series as a member of Samurai Japan, where he pitched effectively for five innings, allowing six hits and one run. His contract was renewed for an estimated 70.00 M JPY, a significant increase of 46.00 M JPY.

In 2021, Uwasawa served as the opening day pitcher. Although he started slowly with an ERA of 6.23 in his first three starts, he turned his season around on April 17, facing Masahiro Tanaka of the Rakuten Eagles, who was making his first NPB appearance in eight years. Uwasawa ended Tanaka's 28-game winning streak in NPB and secured his first win of the season. He then maintained stable pitching, recording 11 consecutive quality starts. This consistent performance earned him his second All-Star Game selection since 2018. Towards the end of the season, his pitching intervals were extended due to fatigue, but he continued to perform as the team's ace. In the final home game of the season for both the team and manager Hideki Kuriyama on October 27 against the Seibu Lions, Uwasawa volunteered to start. He pitched 7.2 innings scoreless, a strong effort. When he was relieved, Manager Kuriyama personally visited the mound for the first time in his 10-year tenure as manager. Although Uwasawa did not get the win, the team secured a walk-off victory. That year, he started 24 games, achieving 12 wins, 160.1 innings pitched, and an ERA of 2.81, all ranking among the top three in the Pacific League. His contract was renewed for an estimated 150.00 M JPY, an increase of 65.00 M JPY.

2.3. Season-by-Season Highlights

• 2015:** Uwasawa struggled in spring training and the early part of the open season. He made his first start of the season in the seventh game of the season against the Orix Buffaloes, pitching a complete game, two-hit, one-run victory. However, his pitching became inconsistent thereafter, and he was removed from the roster three times. After starting against the Orix Buffaloes on July 28, he was removed from the roster for the fourth time the next day due to right elbow discomfort, and did not return to the first team that season. He finished with 5 wins and 6 losses and an ERA of 4.18 in 13 starts. Despite the decline in performance, the team evaluated him as "progressing smoothly for a high school graduate in his fourth year," and he signed for an estimated 24.00 M JPY, an increase of 1.00 M JPY.
• 2016:** On March 23, Uwasawa underwent surgery to remove a synovial fold in his right elbow joint. He aimed to return to action in June, but did not pitch again until August. He ended the season with no first-team appearances for the first time in three years. His contract was renewed for an estimated 10.00 M JPY, a decrease of 14.00 M JPY, which was a 58% reduction, exceeding the 25% limit for salaries under 100.00 M JPY.
• 2017:** On April 7, Uwasawa made his first-team return after 620 days, starting against the Orix Buffaloes, but took the loss after giving up four runs (three earned) in six innings. In his second game back on April 21 against the Saitama Seibu Lions, he struggled, giving up six hits and six walks/hit-by-pitches and six runs in less than four innings. After a stint in the minor league, he made his fourth start of the season on July 2 against the Chiba Lotte Marines, pitching six scoreless innings with four hits, earning his first win in 726 days. He became a regular in the starting rotation in the second half of the season, but often lacked run support despite good pitching. He finished with 4 wins and 9 losses and an ERA of 3.44 in 15 starts. On November 23, it was announced that his uniform number would change to 15 from the following year. On December 4, his contract was renewed for an estimated 24.00 M JPY, an increase of 14.00 M JPY. On December 14, he announced his marriage.
• 2019:** On February 12, the final day of spring training in Arizona, Manager Hideki Kuriyama named Uwasawa as the opening day pitcher for the first time in his career. He started the opening game against the Orix Buffaloes on March 29, pitching six innings and allowing three runs, with no decision. He continued to be part of the starting rotation, but on June 18, during an interleague game against the Yokohama DeNA BayStars, he suffered a left patellar fracture after being hit by a batted ball from Neftalí Soto. He underwent surgery the next day, with a recovery period of five months, effectively ending his season. He finished with 5 wins and 3 losses and an ERA of 3.15 in 11 starts. His contract was renewed for an estimated 60.00 M JPY plus incentives, a decrease of 10.00 M JPY, considering the unavoidable nature of his injury.
• 2020:** Due to the COVID-19 pandemic, the start of the season was delayed from March 20 to June 19. Uwasawa, who had been rehabilitating from his fracture, was ready for opening day. He made his return on June 30 against the SoftBank Hawks. On July 28, against the Orix Buffaloes, he earned his first win in 413 days. On September 1, against the Rakuten Eagles, he pitched his first complete game in 798 days. He finished the season with 8 wins and 6 losses and an ERA of 3.06 in 15 starts. His contract was renewed for an estimated 85.00 M JPY, an increase of 25.00 M JPY.
• 2022:** Under new manager Tsuyoshi Shinjo (BIGBOSS), Uwasawa started his first game of the season (the home opener) in the second series, pitching eight innings and allowing four runs, taking the loss. He subsequently made his first start on four days' rest at BIGBOSS's suggestion. Despite pitching well in some games, including against Rōki Sasaki, he also had several poor outings. By the end of April, he had a record of 0 wins and 4 losses and a league-worst ERA of 4.91. However, he started to recover, pitching seven innings and allowing two runs against the Seibu Lions on May 7 to earn his first win of the season. He stated that "after one win, the form and mechanics felt good." He continued to improve, pitching his first complete game of the season on May 27 against the Yomiuri Giants, allowing two runs (zero earned) in nine innings. In May, he made four starts, recording four wins and an ERA of 0.58, earning his first Monthly MVP award. On July 16, in the seventh inning against the Seibu Lions, he was hit on his right toe by a batted ball from Jansen Witte but continued pitching, allowing no runs in 7.1 innings to earn his fifth win of the season. However, he was removed from the roster the next day. A detailed examination revealed a fracture of the third phalanx in his right toe, and he underwent bone fusion surgery on July 19. He returned to action in a minor league game on August 14 and to the first team on August 20 against the SoftBank Hawks, but took the loss after giving up eight runs in less than five innings. He then pitched a three-run complete game loss against the Seibu Lions on August 30. Although he recorded two wins in his subsequent two starts, he pitched another three-run complete game loss against the SoftBank Hawks on September 20. In his final appearance of the season, which was also the team's last game at Sapporo Dome, on September 28 against the Chiba Lotte Marines, he took the loss after giving up six runs in four innings. Despite his injury absence, he reached the innings pitched qualification for the second consecutive year, but his ERA of 3.38 was the worst in the league. He finished with 8 wins and 9 losses in 23 starts. In the offseason, he signed with "Driveline," a baseball training facility, and traveled to Seattle on December 7 for motion analysis. He also signed a contract for an estimated 170.00 M JPY, an increase of 20.00 M JPY, and requested to be posted for MLB challenge in the 2023 offseason.
• 2023:** Uwasawa was again part of the opening day rotation. He struggled early, experimenting with his pitching form. On April 15, against the Seibu Lions, he had a particularly rough outing, giving up nine runs in less than six innings, including two consecutive bases-loaded walks. He expressed his disappointment, stating it might be "the worst condition I remember." However, he adjusted his pitching form and reviewed his pitching data, gradually regaining his original form. On May 17, against the Seibu Lions, he pitched a nine-inning, 120-pitch, four-hit, two-walk, nine-strikeout, no-run gem, despite being hit by a batted ball in the seventh inning, earning his fifth career shutout (first since June 26, 2018). After April 22, he pitched seven or more innings in 11 consecutive games. By July 4, he had 6 wins and 5 losses with an ERA of 3.03 in 13 starts. The next day, he was selected as a manager's recommendation for his third All-Star Game appearance. In Game 2 of the All-Star series, he pitched one inning, retiring three batters in order. He was removed from the roster before the All-Star break on July 16. He made his first start of the second half on July 28 against the Orix Buffaloes, pitching eight scoreless innings to earn his seventh win of the season. Although he pitched well again on August 18 against the Orix Buffaloes, allowing one run in nine innings, he did not get the decision. He had been winless since his seventh win, but on September 1, against the Orix Buffaloes, he pitched his second shutout of the season, allowing three hits and two walks/hit-by-pitches, striking out seven. This game was attended by 10 scouts from six MLB teams. On September 8, in the seventh inning against the Seibu Lions, he felt a sudden discomfort in his shoulder. He took a two-week break for refreshment. He finished the season with 9 wins and 9 losses, an ERA of 2.96, and a league-leading 170 innings pitched in 24 starts, fulfilling his role as ace. On November 28, he was officially posted for MLB, with negotiations open until January 11 of the following year.

2.4. Posting for MLB and Contract Negotiations

After the 2023 season, the Hokkaido Nippon-Ham Fighters officially posted Naoyuki Uwasawa to Major League Baseball teams, allowing him to negotiate with MLB clubs. This decision came after Uwasawa had expressed his desire to play in MLB and had reportedly met certain performance criteria set by the Fighters. The posting window opened on November 28, 2023, and was set to close on January 11, 2024.

3.1. Tampa Bay Rays

On January 11, 2024, Uwasawa signed a minor league contract with the Tampa Bay Rays just hours before the posting deadline. The contract included a 25.00 K USD signing bonus and a 225.00 K USD annual salary, with a clause that would increase his salary to 2.50 M USD if he was promoted to the major league roster. He was invited to spring training as a non-roster player. Uwasawa stated that he chose the Rays due to their successful history in pitcher development, reportedly declining major league offers from multiple other teams. However, he struggled in spring training, appearing in four games with a record of 0 wins and 1 loss, and an ERA of 13.03. Failing to make the Opening Day major league roster, Uwasawa opted out of his contract, choosing to seek opportunities with other teams rather than joining the Rays' Triple-A affiliate.

3.2. Boston Red Sox

On March 27, 2024, Uwasawa was traded to the Boston Red Sox for cash considerations after triggering an assignment clause in his contract with the Rays. The following day, he was added to the Red Sox's 40-man roster but was optioned to extended spring training, not making the Opening Day roster.

He began the season with the Triple-A Worcester Red Sox. In three starts for Worcester, he recorded 2 wins and 1 loss with an an ERA of 4.80. On April 28, he was recalled from Triple-A and promoted to the major leagues for the first time, wearing uniform number 39. He made his MLB debut on May 2, pitching two scoreless innings against the San Francisco Giants and collecting his first MLB strikeout against Michael Conforto. On May 3, he pitched another two innings against the Minnesota Twins, allowing two hits and one run. Despite a respectable MLB ERA of 2.25 across these two appearances, Uwasawa was optioned back to Triple-A on May 8 to make room for the return of Nick Pivetta from the injured list. He continued to pitch for the Triple-A Worcester Red Sox, making 13 appearances with a record of 3 wins and 3 losses and an ERA of 6.54. After his July 2 outing, he was not given further opportunities. On July 9, he was designated for assignment by the Red Sox to clear a spot on the 40-man roster for Trayce Thompson. He cleared waivers and was outrighted to Worcester on July 13. Uwasawa elected free agency on October 31, 2024. After returning to Japan, he continued to train at the Nippon-Ham Fighters' facilities.

4.1. Fukuoka SoftBank Hawks Contract

On December 18, 2024, it was announced that Naoyuki Uwasawa had signed a four-year contract with the Fukuoka SoftBank Hawks of Nippon Professional Baseball. His uniform number with the Hawks was announced as 10. The total value of the contract was widely reported to be between 800.00 M JPY and 1.00 B JPY.

4.2. Controversy Surrounding Posting System and Return

Uwasawa's return to NPB with a team other than his former club, the Hokkaido Nippon-Ham Fighters, without having acquired domestic free agency rights, marked him as the sixth player in NPB history to do so. Previous instances include Akinori Iwamura (posted by Yakult in 2006, played 4 years in MLB, then joined Rakuten in 2011, acquiring domestic FA rights in NPB in 2011), Kei Igawa (posted by Hanshin in 2006, played 5 years in MLB, then joined Orix in 2012 without acquiring domestic FA rights, and did not play for an NPB team after being released by Orix at the end of the 2015 season), Tsuyoshi Nishioka (posted by Lotte in 2010, played 2 years in MLB, then joined Hanshin in 2013, acquiring domestic FA rights in NPB in 2014), Daisuke Matsuzaka (posted by Seibu in 2006, played 8 years in MLB, then joined SoftBank in 2015, acquiring domestic FA rights in NPB in 2015), and Kohei Arihara (posted by Nippon-Ham in 2020, played 2 years in MLB, then joined SoftBank in 2023, acquiring domestic FA rights in NPB in 2024), all of whom returned to NPB after playing in MLB.

However, Uwasawa's case generated significant public and media discussion due to several specific circumstances:

• His extremely short tenure in Major League Baseball.
• The remarkably low posting fee paid to the Nippon-Ham Fighters, which amounted to only 6.25 K USD, equivalent to less than 1.00 M JPY.
• His decision to pursue a minor league contract in MLB, reportedly against the initial opposition of his former manager, Tsuyoshi Shinjo.
• The fact that he had not yet acquired domestic free agency rights in NPB, meaning that under normal circumstances, he would have been obligated to return to the Fighters if he wished to play in Japan.
• His choice to sign with the SoftBank Hawks, rather than returning to his original team, the Fighters, which many in the public and baseball community felt was the appropriate course of action.

These factors led many baseball fans and former players to criticize the move as a "de facto free agent transfer" or a "loophole" in the existing rules, despite there being no technical violation of the regulations at the time. The issue was even raised by Manager Shinjo at a managers' meeting held on January 20, 2025, where he expressed his disapproval of this trend. In response, on February 20, 2025, during administrative negotiations between NPB and the Japan Professional Baseball Players Association, the Players Association's Secretary-General, Tadahito Mori, requested that "criticism by influential baseball figures that leads to slander and defamation should cease," emphasizing that players returning under such circumstances are not violating any rules.

5.1. Pitching Style and Strengths

Uwasawa employs an overhand pitching motion. His repertoire includes a fastball that can reach up to 94 mph ^{(152 km/h)}, a slider, cut fastball, curveball, forkball, changeup, and two-seam fastball. This wide array of pitches makes it difficult for hitters to anticipate his deliveries. A notable characteristic of his pitching is his ability to maintain consistent performance even after throwing over 100 pitches, showing little change in his pitching from the first to the ninth inning. He possesses strong stamina and mental resilience, often volunteering to pitch complete games even on short rest if the bullpen is fatigued. His fastball is particularly notable for its high spin rate, averaging over 2,600 rpm (compared to the NPB average of 2,200 rpm) and sometimes exceeding 2,800 rpm, which is considered an excellent spin rate even in Major League Baseball.

Due to his tall stature and powerful fastball, Uwasawa was often dubbed "Matsudo's Darvish" upon his professional debut, drawing comparisons to his former teammate, Yu Darvish. Former professional player Takahiro Imanami has commented that while Uwasawa's fastball velocity may have decreased slightly since his early career, he has improved the quality of his fastball, enhanced his command, and developed his off-speed pitches. Uwasawa has a particularly favorable record against the Orix Buffaloes. Although he had a losing record against them (6 wins, 7 losses) until 2017, he has been undefeated against them since 2018, recording 11 consecutive wins. Furthermore, in games he started against Orix where he did not receive a decision, his team ultimately won, extending his personal winning streak against them to 13 games. His first complete game and shutout victory in his career also came against the Orix Buffaloes.

5.2. Awards and Honors

Uwasawa has received several individual accolades throughout his NPB career:

• Monthly MVP: 1 time (Pitcher division: May 2022)
• Sapporo Dome MVP Award: 2 times (Baseball division: 2018, 2021)
• All-Star Game selections: 3 times (2018, 2021, 2023)

5.3. Records and Milestones

Uwasawa has achieved several significant records and milestones in his professional career:

• NPB:**
  • First Appearance, First Start, First Win, First Start Win:** April 2, 2014, against Fukuoka SoftBank Hawks (Fukuoka Yafuoku! Dome), pitching 6 innings, 3 hits, 1 run.
  • First Strikeout:** April 2, 2014, against Fukuoka SoftBank Hawks, striking out Yuki Yanagita in the 2nd inning.
  • First Complete Game (Loss):** July 23, 2014, against Orix Buffaloes (Kyocera Dome Osaka), pitching 8 innings, 1 run, taking the loss.
  • First Complete Game Win, First Shutout Win:** September 15, 2014, against Orix Buffaloes (Sapporo Dome), pitching 9 innings, 3 hits, 6 strikeouts, 0 runs.
  • First Hold:** October 5, 2014, against Tohoku Rakuten Golden Eagles (Sapporo Dome), pitching 3 scoreless innings in relief.
  • First Hit:** June 6, 2018, against Hiroshima Toyo Carp (MAZDA Zoom-Zoom Stadium Hiroshima), a single to center field off Akihisa Okada in the 2nd inning.
  • 1000 Innings Pitched:** May 24, 2023, against Fukuoka SoftBank Hawks (ES CON Field Hokkaido), striking out Tatsuya Yanagimachi in the 6th inning. (364th player in NPB history)
  • MLB:**
    • First Appearance:** May 2, 2024, against San Francisco Giants (Fenway Park), pitching 2 scoreless innings in relief in the 8th inning.
    • First Strikeout:** May 2, 2024, against San Francisco Giants, striking out Michael Conforto in the 8th inning.
    • Uniform Numbers:**

6.1. Marriage and Family

Naoyuki Uwasawa announced his marriage on December 14, 2017.

6.2. Personality and Nicknames

Uwasawa is known for his kind and cheerful personality. During his time with the Nippon-Ham Fighters, he was well-liked by younger players, including Shohei Ohtani. Reporters who covered him for the first time often commented on his pleasant demeanor. He has acquired several nicknames throughout his career, including "Uwacchi" (うわっち_Uwacchi^Japanese) and "Nao" (ナオ_Nao^Japanese).

7.1. NPB Career Statistics

• Statistics as of the end of the 2023 season.
• Bold indicates league leader.

• Statistics as of the end of the 2023 season.
• Bold indicates league leader.

7.2. MLB Career Statistics

• Statistics as of the end of the 2024 season.

• Statistics as of the end of the 2024 season.