Yuki Saito (斎藤 佑樹, Saitō Yūki, born June 6, 1988 in Nitta, Gunma, Japan) is a Japanese former professional baseball pitcher.

However, while he managed to take his team to the semi-finals of the West Tokyo Tournament that summer, he gave up three home runs in the match against Nihon University Third Senior High School in a humiliating mercy-rule loss.

Saito's team faced Nihon University Third High again just months later in the semi-finals of the regional tournament held that fall.

In the spring of 2006, pitching in a national tournament for the first time, Saito took the mound against Kanzei High School of Okayama, going the distance in a grueling match that ended in a tie after fifteen innings as per tournament regulations as well as the rematch that ensued the very next day, eventually leading his team to the win (though it lost to Yokohama Senior High School in the quarter-finals).

As the tournament, various media outlets took a strong liking to Saito's custom of using a blue handkerchief that he kept folded in his pocket to wipe sweat from his face.

Though it had been reported even prior to the tournament that Saito planned on proceeding to college upon completing high school rather than declaring for the Nippon Professional Baseball draft that would be held in the fall, his sensational performance and sudden popularity caused much speculation regarding his decision (particularly by the media).

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."

Going into the spring 2008 season, Saito vowed to win five games and lead to Waseda to a fourth consecutive league title.

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.

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 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.

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.

Saito was dubbed "the second coming of Daisuke Araki" during his high school years (particularly before he won the national championship and became more associated with his other nicknames) for the similarities in their playing styles.