Born on June 21, 1986, in Matsudo, a city in the Chiba Prefecture of Japan, Hideaki Wakui was a ballplayer from an early age, playing softball in elementary school and baseball in junior high school. He would go on to attend Yokohama Senior High School, one of the best baseball high schools in Japan. In 2003, he participated in the the 75th annual spring Koshien tournament. A junior, he was given the ball to start the tournament final against Koryo High School after pitching mostly in relief during the competition, but was touched up for six runs in 3.2 innings in an eventual 15-3 rout. The following year, the senior helped lead his team to the finals of the 86th annual summer Koshien tournament. Wakui was dominant in his first couple of games in the competition, but gave up six runs on fourteen hits in the quarterfinals against Komazawa University Tomakomai High School, knocking Yokohama Senior out of the tournament. The right-hander ended his high school baseball career on a high note, helping lead his school to a Sainokuni Magokoro National Sports Festival championship, and went on to get drafted by the Seibu Lions.
Wakui made the Lions opening day roster in 2005, but failed to make much of an impact, as high pitch counts and his propensity to give up home runs limited the amount of innings he was able to pitch. Despite that, the 19-year-old showed a lot of promise, and with his above-average fastball in the low-90s and plus slider, the results would soon come. He had a much more respectable sophomore season in 2006, finishing the season with a 12-8 record, 3.24 ERA in 178.0 innings, and a solid 2.57 strikeout-to-walk ratio.
In 2007, teammate and Seibu Lions ace Daisuke Matsuzaka left Japan to play for the Boston Red Sox, effectively making Hideaki Wakui the Lions ace. The 21-year-old took the ball from Matsuzaka and ran with it, having a breakout season and establishing himself among the upper echelon of pitchers in Japan at the time. He went 17-10 for the Lions, posting a 2.79 ERA in a career-high 213.0 innings pitched. Wakui wasn’t able to replicate his 2007 success in 2008, having a solid-yet-unspectacular year, but he was able to regain form in 2009, having the best season of his career. Having switched over to wearing the number 18, traditionally reserved for the ace of a pitching staff in Japan, during the winter, the right-hander went 16-6, posting a 2.30 ERA in 211.2 innings pitched. He led the Pacific League in innings pitched, complete games, shutouts, and wins, and was second in ERA and strikeouts. He led enough pitching categories to be named the 2009 Sawamura Award winner, beating out fellow Pacific League pitcher Yu Darvish- though Darvish may have gotten the last laugh, as he was named the 2009 Pacific League MVP.
Wakui had another solid season in 2010, though he seemed to lose steam during the end of the year, posting a 5.79 ERA contributed to fatigue and a minor car accident that he was involved in. When the season ended, the pitcher and Lions management had a public spat, as the two sides were unable to come to terms on what a proper salary for the 2011 season would be. After Wakui stalled on agreeing to their offer of ¥200 million- which represented no raise, as he made ¥200 million for the 2010 season- the Lions balked and told him they were actually thinking of cutting his pay, citing the expectation of more from the ace than a solid season. The pitcher did not budge from his demands, and filed for salary arbitration. “I was amazed by Nippon Ham, “ Wakui said in regards to his situation and how easily the Nippon Ham Fighters came to terms with their ace, Darvish. “If only the [Lions] would just listen [to what I have to say and try to understand my position]. I have no intention of making this hard on them, but when they told me they had no intention of giving me a raise, I just couldn't go along with that. My stats aren't so bad that I need to give up [on a raise]. Other people are supporting me on this. I feel like, come on, even a ¥30 million raise is fine." In mid-January, the case went to an arbitration board, and after 90 minutes of presentation and a staggering 20 hours of deliberation, the committee awarded Wakui 15% raise for the 2011 season based on the pitcher’s testimony.
The ¥253 million man would go on to have another strong season in 2011, even though he dealt with some right elbow discomfort in May and missed a handful of games. In 178.1 innings pitched, the right-hander posted a 2.93 ERA, but a sudden drop in his strikeout rate was a major red flag and a precursor of things to come. In 2012, Wakui was erratic and often ineffective, and to make matters worse, he was suspended for roughly two months after the details of an affair he had became public. He had a second consecutive ineffective season in 2013, seemingly prompting the right-hander to exercise the domestic free agent option he earned that year.
After a handful of teams showed initial interest, Wakui and the Chiba Lotte Marines agreed to a three-year contract with ¥220 million per year plus incentives. The 28-year-old did not exactly make a good first impression in his first year with the Marines, posting a 4.21 ERA over 164.2 innings pitched, but fared better in the final two years of his contract. At the end of the 2016 season, Wakui’s three-year contract with the Marines expired. He was rumored to have been interested in playing in the United States, but in late January, the right-hander signed a multi-year extension with the Marines. Wakui had a down season, going 5-11 with a 3.99 ERA in 158.0 innings, earning his international free agent option at the end of the season. With the blessing of the team, he opted out of his contract in early November and exercised his international free agent option.
Like other Japanese pitchers, Wakui utilizes a delivery that is highly unconventional among North American sensibilities. He uses a three-quarters arm slot. During his delivery, he uses a large leg kick and slight twist of the body to hide the ball. Uniquely, during the pause of his delivery, he straightens and twists his left leg before striding forward and throwing the ball. Despite the many moving parts, Wakui has been able to keep his release point relatively consistent throughout the course of his career, though he does often drag his arm behind his body.
When he broke into the league, the 6’1”, 190-pound Wakui possessed a four-seam fastball that sat in the low-90s, which would be considered a better-than-average pitch in Japan, while in America, it would be considered roughly average for a right-hander. In the years since, injuries and his pitching mechanics have diminished the velocity that the pitch is thrown. In more recent years, his fastball generally has sat in the upper-80s, which is below-average for a right-handed pitcher. The same can be said of his two-seam fastball, which now averages roughly the same.
Wakui supplements his fastball- which he generally uses about 50% of the time- with an assortment of breaking balls. He throws a slider that sits in the mid-80s, a changeup that sits in the high-70s, and a curveball that sits in the high-60s. Generally speaking, he is a fastball-slider pitcher, though when he was pitching out of the bullpen in 2012 and 2013, he threw the slider less and the changeup more, becoming more of a fastball/changeup pitcher.