- Bats Right, Throws Right
- Height 5' 11", Weight 187 lb.
Naoyuki Shimizu struggled through a shoulder injury that left him with one win in college and two for Toshiba in the industrial leagues. In 1998, he was chosen in the second round of the NPB draft by the Chiba Lotte Marines. He first pitched regularly for the Marines in 2000, getting smacked around to a 3-6, 6.12 tune with 66 walks and a league-leading 13 wild pitches in 100 innings. The next year, Shimizu went 6-2 with a 3.74 ERA out of the bullpen.
In 2002, Shimizu went 14-11, but with a 4.56 ERA and led the Pacific League with 28 home runs allowed. The next season, the 27-year-old turned the corner with a 15-10, 3.13 season. His control had improved significantly, with 53 walks and 9 wild pitches in 204 1/3 innings. He made his first All-Star team and led the PL in innings. He was fourth in the league in victories and third in ERA, trailing only Kazumi Saitoh and Daisuke Matsuzaka.
2004 was a losing year for Shimizu (10-11) but his ERA was still good (3.40). On Opening Day, he outdueled Matsuzaka. Despite being 4th in the PL in earned run average, he led the league in defeats. He missed time to participate in the 2004 Olympics, in which he beat Greece. In 2005, Naoyuki again went 10-11, now with a 3.83 ERA. On Opening Day, he lost to the Rakuten Golden Eagles in their first game ever. He led the Pacific League with 27 gopher balls given up and did not finish in the top 10 in any of the key positive statistics (he was 5th with seven complete games). He still made his second All-Star team and got the game one start in the 2005 Japan Series, in which he allowed one run in 7 innings before the game was called due to fog.
Saying he would like to be posted after the 2006 season, Shimizu pitched for Japan in the 2006 World Baseball Classic. He threw in two games out of the bullpen, saving one and striking out 6 in 4 1/3 innings, with a 4.15 ERA. In the 2006 season, he was 10-8 with a 3.42 ERA and failed to make the All-Star team. He was not posted at year's end.
Shimizu struggled in 2007, going 6-10 with a 4.78 ERA and .318 opponent average. He tied for 4th in the PL in losses, was second in hits allowed (189, trailing Hideaki Wakui), led in runs allowed (86) and was second in earned runs allowed (77, 2 behind Masahiro Tanaka).
Naoyuki was 13-9 with a 3.75 ERA in a resurgent 2008. He tied Shunsuke Watanabe for 4th in the PL in wins, tied for 6th in losses, was 10th in innings (165 2/3), was third in complete games (7, behind Yu Darvish and Toshiya Sugiuchi), tied for second in runs allowed (81) and was 6th in earned runs allowed (69).
Shimizu had a 6-7, 4.42 record and allowed a .305 average in 2009. He was among the league leaders in hits allowed (177, 2 behind Hisashi Iwakuma), runs allowed (75, 4th) and earned runs allowed (71, 4th).
After the 2009 season, the Marines traded Shimizu to the Yokohama BayStars in exchange for Takumi Nasuno and Toshio Saito. He was 10-11 with a 5.40 ERA in 2010, placing third in the Central League in losses (behind Dicky Gonzalez and Shigeru Kaga), led in homers allowed (26, 3 more than Eric Stults or Masato Nakazawa), was second in hits allowed (203, 6 behind Masanori Ishikawa), led in runs allowed (98, 14 more than Tetsuya Utsumi) and led in earned runs (93, 15 more than Gonzalez). He was 2-4 with a 4.62 ERA for Yokohama in 2011 to end his NPB career at 105-100, 4.16.