"Anyone who does something 365 days a year might not be quite as good as they'd like. This is a different mindset -- it's about trying to keep fresh and excited about racing."
That's not to say Rosario hasn't worked hard to get where he is.
But you get the feeling that if he'd had been just that little bit taller, he would have chosen professional baseball instead of the track.
"Every boy in the Dominican Republic plays baseball. And everyone thinks they're going to play professionally," said Anderson.
"They play it every day of the year. They get out of school and play it until it gets dark. So baseball is really embedded in the national psyche."
Growing up on a farm, Rosario was just five years old when he started riding horses. But it wasn't until he started jockey school that he first laid eyes on the country's one and only race track.
Once he did, he was focused on success, moving to San Francisco and working his way up to the top circuits.
Today he is the only jockey from the Dominican Republic to win the Kentucky Derby -- doing so just weeks after his nation also won the World Baseball Classic.
Now it seems that for the very first time, the country's most famous sports star may not be from the ball park after all.