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.
In this case, semicolons would help to clearly separate the different roles and names, avoiding confusion that might arise from using commas alone. The revised sentence would look like this:
The captains of the high-school softball team are pitcher: Marisa Martino; outfielder: Rachel Morrison; and catcher: Lisa Fiore.