The sentence that requires semicolons instead of commas is:
"The captains of the high-school softball team are pitcher, Marisa Martino, outfielder, Rachel Morrison, and catcher, Lisa Fiore."
This sentence lists roles along with names, which can get confusing with just commas. Using semicolons to separate the different captain roles and names would clarify the list. It could be rewritten as:
"The captains of the high-school softball team are pitcher: Marisa Martino; outfielder: Rachel Morrison; and catcher: Lisa Fiore."