After playing college baseball for Tohoku Fukushi University, Sasaki was drafted with the seventh pick in the first round of the 1989 draft by the Yokohama Taiyō Whales in Japan's Central League. He played for them from 1990–1999, before joining the Seattle Mariners in 2000. He joined a bullpen that had been one of the worst in the Major Leagues, and during his rookie year won the closer job from a floundering José Mesa. Sasaki's out pitch, a devastating split-fingered fastball that drops when arriving at home plate, was nicknamed "The Fang" by Mariners radio announcers. He complemented it with a four-seam fastball that topped out at mid-90s. Sasaki maintained a rigorous throwing program, sometimes at odds with club management, that saw him throw up to 100 pitches following games in which he did not appear. Sasaki's transition to American baseball began with his being named American League Rookie of the Year. For three years, along with Jeff Nelson and Arthur Rhodes, Sasaki was an integral member of the back of Seattle's bullpen. He decided to leave the Mariners before the last year of his contract in 2004, giving up $8.5 million, citing his desire to be with his family in Japan. According to the Seattle Post-Intelligencer, however, Sasaki's real reason for returning to Japan was pressure from ownership, due to his "indiscreet philandering". Sasaki resumed his career with the BayStars upon returning to Japan, where he pitched for another year. But in his second year back, nagging knee and elbow injuries resulted in his release from Yokohama and subsequent retirement. His last official appearance came as a cameo against the Tokyo Giants on August 9, 2005, as he struck out his longtime friend and rival Kazuhiro Kiyohara in a game played at Fullcast Stadium Miyagi in his hometown. In addition to his Rookie of the Year award, Sasaki set several Japanese professional baseball records, including saves and save opportunities for a single season in 1998; he was twice selected to play in the All-Star game, and was selected to eight All-Star teams in Japan. Sasaki's 37 saves in his rookie season with the Seattle Mariners remained a Major League Baseball record for saves by a rookie until Neftalí Feliz broke it in 2010 with 40.
Personal life
In 1991, Sasaki married former idol singer Kaori Shimizu. Together they had two children. After returning to Japan in 2005, Sasaki continued his affair with actress Kanako Enomoto, who was 13 years his junior. When Enomoto became pregnant, Shimizu divorced Sasaki on March 18, 2005. Enomoto gave birth prematurely on April 29, 2005. Sasaki's interest in sports extend outside baseball. In 2002 and 2003, he lent his name to Formula Nippon, an auto racing series in Japan. His Team 22 won two races in that time. Also is a horse racing owner, his horse Vivlos won the 2017G1 Dubai Turf race on Dubai World Cup Night and Cheval Grand winner of the prestigious G1Japan Cup. He is currently the general representative of D'Station Racing in Super GT series. Sasaki has appeared as a judge on the Iron Chef television program. He had a side recording career, with an album of his vocals over techno beats. Sasaki chose 22 for his uniform number because he was born at 2:22 on February 22. The BayStars have permanently honored his number.
