- Bats Left, Throws Left
- Height 6' 0", Weight 162 lb.
- High School Asahikawa Kogyo High School
Hoshino was a 5th-round pick of the Hankyu Braves out of high school. He went 1-2 with a save and a 4.47 ERA in 1985, walking 39 in 46 1/3 innings as a rookie. He went 9-8 with a 3.88 ERA in 1986 to finish 9th in the Pacific League in ERA, between Hisashi Yamada and Yoshiaki Nishikawa. He was 11-12 with a 3.87 ERA, 170 strikeouts in 179 innings and a .214 opponent average in 1987, when he made his first PL All-Star team. He led the league with six shutouts that season.
The junkballer was 13-9 with a 3.06 ERA and .220 opponent average in 1988 and made a second All-Star team. He finished 8th in the circuit in ERA. An All-Star again in 1989, the Hokkaido native went 15-6 with a 3.48 ERA, though he led the league with 11 wild pitches. He was 6th in ERA, between Hisanobu Watanabe and Tomoo Watanabe.
The Orix hurler slipped to 14-9, 4.02 in 1990 and gave up 33 home runs, tying Hideyuki Awano for the PL lead. That year, he was embarrassed by his catcher Satoshi Nakajima, who caught one of Hoshino's slow curves and fired the ball back to the mound, causing both teams to erupt in laughter. Despite Hoshino's anger over the stunt, Nakajima would repeat it in bullpen sessions. He rebounded to 16-10, 3.53 with a save in 1991 and made his fourth All-Star team while finishing 10th in ERA.
Nobuyuki was 13-9 with a 3.62 ERA and 175 strikeouts in 1992 while tying Hideo Nomo for the league lead with five shutouts, Hoshino's last time as a league-leader. He again was 10th in ERA. In 1993, he had a 10-12, 3.35 season and was 10th in ERA for the third straight year. He had a 10-10, 3.58 record in 1994 and was 7th in ERA, between Yoshinori Sato and Toyohiko Yoshida.
In 1995, the crafty southpaw turned in a 11-8 record with a 3.39 ERA. He returned to his old familiar spot of #10 in the PL in ERA and made his 5th All-Star team. In the 1995 Japan Series, he allowed one run in 4 1/3 innings as Orix fell to the Yakult Swallows. Hoshino improved to 13-5, 3.05 in 1996 while making his sixth All-Star squad. He was 5th in ERA between Yukihiro Nishizaki and Koji Noda. He started games one and five of the 1996 Japan Series, allowing three runs in eight total innings and getting two no-decisions, as the BlueWave won their only Japan Series title.
Hoshino made his final All-Star team in 1997, when the 31-year-old was 14-10 with a 3.24 ERA. He placed 8th in ERA, between Fumiya Nishiguchi and Noda. He struggled at 6-10, 5.12 with a .310 opponent average in 1998 but rebounded to 11-7, 3.85 in 1999.
Hoshino left Orix after 15 seasons to sign with the Hanshin Tigers. He was 5-10 with a 4.04 ERA in 2000 and 1-2 with a 4.60 ERA in 2001. His lone win that year was the 4,000th in franchise history, on August 12. He ended up with a 2-1, 2.39 season in 8 games in 2002.
Overall, Hoshino was 176-140 with two saves and a 3.64 ERA in 427 NPB games. He struck out 2,041 in 2,669 1/3 innings. Through 2010, he was 18th in NPB history in whiffs (between Masaji Hiramatsu and Hiroshi Matsuoka), 27th in walks (927, between Yutaka Enatsu and Hisashi Yamada), tied for 22nd in runs allowed (1,191, even with Masumi Kuwata) and 18th in earned runs allowed (1,079, between Kuwata and Naoki Takahashi).