What are som possible careers behind the scenes in professional sports that I can explore?

Sports are a product and just like any other business they need support. So that answer is, you can do almost anything from Finance, HR, Technology, PR, etc. Focus on what drives your interest in sports. Is it the stories of great games and athletes? Then consider writing or media production as a career. Is it the numbers behind the games? Load up on the statistics classes and become a researcher who supports the writers and media producers. From medicine to marketing, you can pick a career and steer it toward the sports world. Focus locally with local sports stations or teams to gain some experience and get to know everyone you see in those workplaces. From there you can pick what you like and dislike and steer your course accordingly.

The NBA, NFL and every other professional sports organization and its teams all operate like any other company, meaning there are several types of jobs/careers you could pursue (PR, marketing, HR, accounting, operations, administration, etc.). When you get to college, make sure to be ask active in your athletics department as possible. Volunteer in a department if you have the time, or if you are busy playing your sport, talk to your coaches and sports information director so they know being in athletics is a career path you've chosen. Ask for their help in making connections so you can gain experience in the area you are interested in. Working in sports is a highly competitive field. Making connections and gaining experience will be key to getting ahead of the other candidates.