When Ichiro was second grade, he started training skill of baseball such as throwing, batting, and catching, with his father. This training was done with his father everyday (365 days) after school for four years. Even though his father was busy for his work, he taught those skills everyday for his son. Then Ichiro's father also taught importance of putting a lot of effort for accomplishing the purpose to be a baseball player.
Moreover, Ichiro's father even helped Ichiro after training. Every after training, His father massages Ichiro's arms and legs. I think his father more tired than Ichiro as he always taught after his work. But he was still dedicating himself to Ichiro's training.
His father's help can be considered essetial for his success in MLB. Also, in other words, he would not exist as a MLB player without his father, I think.