There are many multi sport athletes in the high school ranks and elite athletes in college are drafted in multiple professional leagues. You can see known lists here including baseball:

https://en.wikipedia.org/wiki/List_of_multi-sport_athletes

The list for college and high school would be huge. There is such a thing as athletic skill, I’ve heard it called a kinesthetic gift. People with particularly good builds, strengths, speed, agility, etc. can train those attributes across several different disciplines. As you get higher and more elite you will eventually have to specialize. “Jocks” in high school frequently played multiple sports and many lettered in multiple as well.