As a player, Yoshimi spent his entire 15-year career in Nippon Professional Baseball (NPB) with the Chunichi Dragons.

Yoshimi started playing baseball in Grade 2 of elementary school.

[1] On September 10, 2006, Yoshimi was registered for the first-team for the first time and debuted against the Hiroshima Toyo Carp with an untarnished 1.1 innings.

On September 18, Yoshimi would claim his first win, this time against the Yokohama DeNA Baystars where he pitching 5 innings for 2 earned runs.

In 2007, Yoshimi was named MVP of the Japanese Farm Team National Championships and would later take part in the Dominican Winter League where he would pitch for Estrellas Orientales.