|Chunichi Dragons – No. 36|
|Born:May 25, 1992|
|8 July, 2017, for the Chunichi Dragons|
|NPB statistics |
Ishioka started playing rubber-ball baseball in elementary school and while at junior high school played for the Kobe Sky Dragons.
He played for St Michael's Senior High School and in Autumn of his junior year nailed down his spot as starting first baseman. In his senior year, his school played in the Spring senbatsu tournament where Ishioka struck out twice in the first and only game leading to the team's exit. After graduation, he went to play for JR East.
Ishioka contributed to JR East's victory in the 82nd Intercity Baseball Tournament, picking up rookie player of the tournament honours. In his second year as third batter in the line-up, he helped the team to become runners-up and in 2014 he was selected to represent Japan at the 17th Asian Games where he along with future team-mates Issei Endō, Masataka Iryo and Shun Ishikawa claimed the bronze medal.
On 22 October 2016, at the 2015 Nippon Professional Baseball draft, Ishioka was the 6th pick for the Chunichi Dragons. On 25 November, he signed a contract worth ￥5,000,000 per year with a \10,000,000 sign on bonus.
Ishioka was the only rookie of the 2015 draft class not to make an appearance during the 2016 season. He did however perform well in the Western League farm team registering a .289/.355/.329 slash line.
He was selected alongside team-mates Takuma Kato, Shota Suzuki, Ryosuke Nomura, Hayato Mizowaki and Hiroki Kondoh to represent the Western League selection at the 2016 Asian Winter League held in Taiwan.
- "橋戸賞はＪＲ東日本の松本／都市対抗" (in Japanese). Nikkan Sports. 1 November 2014. Retrieved 23 August 2016.
- "The 17th Asian Games - Japanese National Baseball Team Candidate Training Camp". Samurai Japan - The Official website of the Japan national Baseball team. 29 November 2013. Retrieved 23 August 2016.
- "Overview of the 17th Asian Games". Samurai Japan - The Official website of the Japan national Baseball team. 1 October 2014. Retrieved 23 August 2016.
- "中日ドラフト６位石岡、契約金5000万で仮契約" (in Japanese). Nikkan Sports. 25 November 2015. Retrieved 23 August 2016.
- "中日ドラ６石岡「残念」腰の椎間板ヘルニア手術へ キャンプ不参加" (in Japanese). Sponichi. 26 January 2016. Retrieved 23 August 2016.
- "2016 Chunichi Dragons Individual Batting (Western League)". Nippon Professional Baseball. Retrieved 7 October 2016.
- "【中日】アジアＷＬ派遣の４野手「合言葉は開幕１軍」" 【中日】アジアＷＬ派遣の４野手「合言葉は開幕１軍」 [Chunichi: 4 position players loaned to Asian winter league; "motto is starting day roster".] (in Japanese). Sports Hochi. 22 November 2016. Retrieved 15 December 2016.