In the beginning he is an member of the East Mifune who doesn't train and even bullied Komori alongside Oikawa, their "group" chief was Yamane. When Yamane started playing baseball again, the two came along.

After the baseball season was over, Goro returned to Japan. There he learned from Toshi that there is going to be a Baseball World Cup the following year hosted in America. 
(Source: AniDB)

Next season of Major. 
After the final game of his Seishuu team against the goal he set himself, Kaidou - the team he left to play against, Gorou has no feelings of remorse anymore. Again he decides to take a step forward and challenge himself. 
Saying one more time good bye to Shimizu and his friends, he leaves for the USA, where he plans on competing in the Minor League. 
This is where Season 4 starts, in a country that`s foreign to him, a baseball style that`s unknown to him and new friends and strong rivals who share the same love to the game as him. Accompany Gorou in his neverending quest for new challenges. 
(Source: AniDB)

The story of Major follows the life of Goro Honda, from kindergarten to being a professional baseball player, seeking and overcoming tremendous challenges.

Muta