Yabu injured his arm early in his childhood playing baseball, but never got it properly looked at. Though he continued to pitch, he did not receive attention from scouts until he joined Asahi Life Insurance of the industrial leagues. Hanshin selected him with their first pick in the 1993 draft. He would wear #18.
Yabu made the all-star team as a rookie (voted in by fans, no less) and his 9-9 record on a terrible Hanshin team was enough to earn him Rookie of the Year honors as well. He led the league the following season with 13 losses. The streak continued in 1996, as he tied teammate Toshiro Yufune for the title of shame. He also led the league in hits against, though he also made more starts than any other pitcher that year with 30. It would be the first of three seasons in which Yabu was named Opening Day starter. In 1998 he finally got more wins than losses, and put up double digits in victories for the third straight season. Unfortunately, that streak came to a crashing halt in 1999, as his 16 losses were once again most in the league. It was just the start of Yabu’s miseries though, as he reached double digits in losses for the sixth straight season in 2000, and missed most of 2001 to injury.
In 2002, Yabu changed his uniform number, and with it came a slight change in his fortunes as a pitcher. For the first time in his career, he finished with a record more than one game over the .500 mark. He did even better in 2003, finishing with a strong-looking 8-3 record. Unfortunately, he did not earn a spot on the Nippon Series roster. Following a mediocre 2004 season, Yabu declared his intention to attempt a career change by declaring himself an eligible international free agent.
Yabu signed with the Oakland Athletics in January 2005, made the roster and won four games, but did not figure into the club’s future plans. He was released at season’s end. The following year, he signed with the Colorado Rockies but before the season began, he retired from baseball. He ended up signing with the Potros de Tijuana on June 29th, though. He then spent the 2007 season training on his own, as he did not receive any offers to play in the majors. He decided that year that he wanted to give the majors one more try, even taking a minor league contract if that’s what he got offered.
Yabu ended up making the San Francisco Giants’ Opening Day roster in 2008. On April 14th, he got his first major league win in 3 years, becoming the first Japanese Giants pitcher to win a game for the club since Masanori Murakami did so on September 30, 1965. On May 30th, Yabu came in to help the team out of a jam. With runners on first and second and no one out, all it took was one Yabu pitch to induce a triple play, ending the inning. That season would be the end of his MLB career, in essence, as he failed to hold his roster spot after 2009 spring training, and despite an attempt with the AAA Fresno club, he was released for good on July 11th.
Midway through the 2010 season, Yabu unsuccessfully auditioned for the Chiba Lotte Marines, but a few days later, signed on with the Rakuten Eagles. He had a disastrous debut, though, giving up four runs in just ⅓ inning. He played in 11 more games out of the bullpen, but was released by the club at season’s end.
Yabu returned to the Hanshin Tigers as a pitching coach at the start of the 2011 season. He worked three seasons in the role (the last of which was with the farm team), but was released at the end of the 2013 season. He now appears on a morning talk show, Ce Matin, as a Tigers analyst, and occasionally does guest commentary on Hanshin Tigers TV broadcasts. At times, he can also be seen on J-Sports doing play-by-play for Major League games.