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 contains lists within a list (captain roles paired with names) and would benefit from semicolons for clarity. It should be revised to:
The captains of the high-school softball team are pitcher: Marisa Martino; outfielder: Rachel Morrison; and catcher: Lisa Fiore.
(Note: If you were looking for a different format of correction or explanation, please clarify!)