As for her bicep move, Sister Mary Jo said it was to relax her nerves.
"I had to do something to take my mind off it," she told WLS. "It's too awkward to just stand and throw from the jump and I had to just do something to put me in motion."
She also decided to pitch from the top of the mound rather than closer to the plate.
“As an athlete, you gotta be all in, and I knew that my coaches and my teammates, when they saw that, they would be like, ‘You gotta do the real thing,’ and it's all or nothing,” she said. “I had to do it from the top.”
Sister Mary Jo said she was chosen for the honor at the game, where Marian Catholic was celebrating its 60th anniversary, because of her athleticism.
“I had a little bit of athletic ability,” she said. “I was probably the most likely candidate, because of my youth and my agility.”
The Sox lost to the Royals 3-1, but the impression Sister Mary Jo left on the crowd beforehand remained.
“She was pretty good, actually,” White Sox manager Rick Renteria said. “We talked to her a little bit but before we were talking to her, she was talking to someone and she wanted to warm up. She had a mitt and a ball. She gave him the mitt. She stepped back at about 45 feet and threw a bullet.”