2007 In 2007, Saito enrolled in
Waseda University as a
sociology major, pitching in the opener of the spring
season of the
Tokyo Big6 Baseball League against the
University of Tokyo on April 14. He threw six shutout innings, striking out eight and allowing just one hit and earning the first
win of his college career. He earned the trust of
head coach Atsuyoshi Otake and was sent to the mound in the crucial second game of series several times, including the pivotal game against arch-rival
Keio University on June 3 that clinched their second consecutive league title. Saito finished the season with a 4-0
record and a 1.65
ERA, starting four games and
closing out two others in situations that would be recorded as
saves in
professional leagues (there are no official saves in the Tokyo Big6 Baseball League). He was chosen to the league's Best Nine, the first time a freshman pitcher had ever won the award in the spring season, and was also named the league
Most Valuable Player in
online fan voting. That June, Saito took the mound as Waseda's ace in the second-round match, semi-finals, and finals of the 56th All-Japan University Baseball Championship Series, earning wins in the latter two games and leading the school to their first national championship in 33 years. Saito was also named the tournament MVP for his efforts. A month later, in July 2007, Saito was chosen to play for Japan in the 36th Japan-USA University Baseball Championship Series. He started in Game 3 of the series and came away with the win, becoming the first freshman to play for Japan to earn a win in the history of the tournament. However, he could not find his location in Game 5 after coming on in
relief, ultimately being charged with the
loss. After the game, he commented to the American media, "There's a part of me that would like to play in the majors after experiencing professional baseball in Japan once." Saito took the mound for the fall season opener as well, becoming the first pitcher in 80 years to start and win the opener of both the spring and fall seasons as a freshman (then-Keio pitcher Saburo Miyatake accomplished the feat in 1927). He pitched the first
complete game of his college career in the fourth game against
Hosei University on September 25 and topped the effort with a 15-strikeout (a personal high) complete-game shutout in the rubber game against Keio on October 30, becoming the winning pitcher in the title-clinching game for Waseda for the second consecutive season. He finished the season with a 4–0 record and an 0.78 ERA in innings, leading the league in wins and ERA and winning both the Best Nine and Most Valuable Player (as chosen by the fans) awards a second time. In the 38th Meiji Jingu Tournament that followed, he started all three games, leading Waseda to a match-up with
Toyo University in the tournament finals on November 14. However, though he pitched six shutout frames and matched Toyo's ace (and current
Fukuoka SoftBank Hawks pitcher) Shota Ohba inning for inning, the bullpen gave up the go-ahead run after Saito left the game and Waseda fell just short of the tournament championship.
2008 Going into the spring 2008 season, Saito vowed to win five games and lead to Waseda to a fourth consecutive league title. However, the spring season turned out to be a frustrating experience for Saito. In a May 19 start against
Meiji University, Saito was hit in the right thigh by a sharp come-backer (a line drive right back to the pitcher), forcing him to leave the game. Waseda went on to lose the game (the loss being charged to Saito), diminishing their chances of winning the league title. In his next game against Keio on June 1, Saito gave up two home runs, losing consecutive starts for the first time in his college career. It was also the first time he gave up multiple home runs in a game since the National High School Baseball Championship finals in 2006. Saito finished the season at just 3–2, relinquishing Waseda's stronghold on the league title to Meiji. Saito spent much of the summer overseas, playing in the
IBAF World University Baseball Championship in the
Czech Republic and taking part in a tour of Brazil with the rest of the Waseda team. He placed a greater emphasis on running in his workouts. Just how effective Saito's effort to build stamina during the summer would be quickly became evident during the fall season. In one particular stretch from October 11 to October 20, Saito started five of the seven games Waseda played against Hosei and Meiji, going 3-1 and throwing 525 pitches in a 10-day span. Saito held Keio to one run over seven innings in the title clincher on November 1, marking already the third time in his college career that he had pitched in a title-clinching game. He followed the performance up with another win over Keio two days later, finishing the season with a league-leading (and personal-best) 7–1 record and notching at least one win against each of the five other teams in the league (Tokyo, Hosei, Meiji, Keio, and
Rikkio), earning him his third selection to the Best Nine Award.
2009 Saito started the spring 2009 season off well, pitching seven shutout innings while striking out 10 and allowing just three hits in a resounding 11–0 victory over the University of Tokyo in the season opener held April 11. However, he had one of the worst outings of his career against Hosei University on April 28, lasting just four innings and giving up six runs (the most in his college career thus far) on six
hits, three
walks and three
hit-batters en route to an 8–4 loss. He rebounded with a stellar outing against Rikkio on May 2, striking out 12 and allowing just two hits over eight shutout innings in a 3–0 victory. ==Professional career==