Two-time winner and defending champion Japan has published a 34-man provisional roster for the 2013 World Baseball Classic. Samurai Japan’s squad consists of 16 pitchers, three catchers, eight infielders and seven outfielders. Not one player from Major League Baseball is on the preliminary roster, which is comprised solely from Nippon Professional Baseball teams. Stars like Yu Darvish, Ichiro Suzuki, Hiroki Kuroda and Norichika Aoki already had announced a couple of weeks ago that they would sit out the 2013 WBC. Japan is facing Cuba, China and Brazil in the first round, playing on home soil in Fukuoka.
| Pos | Name JPN | Name ENG | Team | DOB | Ht | Wt | T | B |
| P | 杉内 俊哉 | Sugiuchi, Toshiya | Yomiuri | Oct. 30, 1980 | 175 | 82 | L | L |
| P | 内海 哲也 | Utsumi, Tetsuya | Yomiuri | Apr. 29, 1982 | 186 | 90 | L | L |
| P | 山口 鉄也 | Yamaguchi, Tetsuya | Yomiuri | Nov. 11, 1983 | 184 | 86 | L | L |
| P | 澤村 拓一 | Sawamura, Hirokazu | Yomiuri | Apr. 3, 1988 | 183 | 96 | R | R |
| P | 山井 大介 | Yamai, Daisuke | Chunichi | May 10, 1978 | 179 | 82 | R | R |
| P | 吉見 一起 | Yoshimi, Kazuki | Chunichi | Sep. 19, 1984 | 182 | 91 | R | R |
| P | 浅尾 拓也 | Asao, Takuya | Chunichi | Oct. 22, 1984 | 182 | 75 | R | R |
| P | 前田 健太 | Maeda, Kenta | Hiroshima | Apr. 11, 1988 | 182 | 73 | R | R |
| P | 今村 猛 | Imamura, Takeru | Hiroshima | Apr. 17, 1991 | 183 | 83 | R | R |
| P | 能見 篤史 | Nomi, Atsushi | Hanshin | May 28, 1979 | 180 | 72 | L | L |
| P | 牧田 和久 | Makita, Kazuhisa | Seibu | Nov. 10, 1984 | 177 | 82 | R | R |
| P | 涌井 秀章 | Wakui, Hideaki | Seibu | Jun. 21, 1986 | 185 | 85 | R | R |
| P | 攝津 正 | Settsu, Tadashi | Softbank | Jun. 1, 1982 | 181 | 90 | R | R |
| P | 大隣 憲司 | Otonari, Kenji | Softbank | Nov. 19, 1984 | 175 | 85 | L | L |
| P | 森福 允彦 | Morifuku, Masahiko | Softbank | Jul. 29, 1986 | 171 | 65 | L | L |
| P | 田中 将大 | Tanaka, Masahiro | Rakuten | Nov. 1, 1988 | 188 | 93 | R | R |
| C | 阿部慎之助 | Abe, Shinnosuke | Yomiuri | Mar. 20, 1979 | 180 | 97 | R | L |
| C | 相川 亮二 | Aikawa, Ryoji | Yakult | Jul. 11, 1976 | 182 | 86 | R | R |
| C | 炭谷銀仁朗 | Sumitani, Ginjiro | Seibu | Jul. 19, 1987 | 180 | 93 | R | R |
| INF | 村田 修一 | Murata, Shuichi | Yomiuri | Dec. 28, 1980 | 177 | 92 | R | R |
| INF | 坂本 勇人 | Sakamoto, Hayato | Yomiuri | Dec. 14, 1988 | 185 | 80 | R | R |
| INF | 井端 弘和 | Ibata, Hirokazu | Chunichi | May 12, 1975 | 173 | 75 | R | R |
| INF | 鳥谷 敬 | Toritani, Takashi | Hanshin | Jun. 26, 1981 | 180 | 77 | R | L |
| INF | 稲葉 篤紀 | Inaba, Atsunori | Nippon Ham | Aug. 3, 1972 | 185 | 94 | L | L |
| INF | 松田 宣浩 | Matsuda, Nobuhiro | Softbank | May 17, 1983 | 180 | 85 | R | R |
| INF | 本多 雄一 | Honda, Yuichi | Softbank | Nov. 19, 1984 | 174 | 72 | R | L |
| INF | 松井稼頭央 | Matsui, Kazuo | Rakuten | Oct. 23, 1975 | 177 | 85 | R | S |
| OF | 長野 久義 | Chono, Hisayoshi | Yomiuri | Dec. 6, 1984 | 180 | 83 | R | R |
| OF | 大島 洋平 | Oshima, Yohei | Chunichi | Nov. 9, 1985 | 176 | 74 | L | L |
| OF | 糸井 嘉男 | Itoi, Yoshio | Nippon Ham | Jul. 31, 1981 | 187 | 88 | R | L |
| OF | 中田 翔 | Nakata, Sho | Nippon Ham | Apr. 22, 1989 | 182 | 95 | R | R |
| OF | 内川 聖一 | Uchikawa, Seiichi | Softbank | Aug. 4, 1982 | 185 | 88 | R | R |
| OF | 聖澤 諒 | Hijirisawa, Ryo | Rakuten | Nov. 3, 1985 | 179 | 72 | R | L |
| OF | 角中 勝也 | Kakunaka, Katsuya | Lotte | May 25, 1987 | 180 | 80 | R | L |