The Cardinals prompted Tuivailala to debut a new pitch -- akin to a cutter -- in the one-inning relief appearance. It was a pitch Tuivailala experimented with occasionally in Spring Training, but one that he had never thrown in a game at any level.
Tuivailala estimated that catcher Tony Cruz called for the pitch five or six times in the 14-pitch appearance.
"It was a good opportunity for me to work on that stuff," Tuivailala said. "I'm happy with how it came out. I'm excited to keep working on it."
"I think [it] is going to completely redefine how he throws," Matheny said. "He was a little apprehensive, but it ended up working out real well for him. ... It's a pitch you don't have to be quite so fine with, too. Now he has something else that he can throw more toward the middle of the plate."
Tuivailala believes that the pitch, which he throws with his curveball grip, will make his four-seam fastball more effective.
Though the Cardinals introduced the pitch in spring, Tuivailala was so focused on improving his curveball and changeup at the time that he didn't have much time to toy with the new offering. He threw it occasionally on the side and continued to experiment with the grip at the end of his long-toss sessions while with the Triple-A team.
On Tuesday he saw what's possible when throwing the cutter with conviction.
"He's an athlete," Matheny said. "This kid was drafted as a shortstop, and we've talked about how those kinds of pitchers can typically grab a new pitch and run with it. With the high velocity he has, if he has something else ... And that's a pitch you're seeing a lot of guys throwing a high percentage of the time. I'm excited about what that can possibly open up for him."
Jenifer Langosch is a reporter for MLB.com. Read her blog, By Gosh, It's Langosch, follow her on Twitter @LangoschMLB, like her Facebook page Jenifer Langosch for Cardinals.com and listen to her podcast. This story was not subject to the approval of Major League Baseball or its clubs.