MESA, Ariz. -- Since Nick Nastrini was a young baseball enthusiast playing in the backyard with his brother, he had a Major League dream.

That dream, though, didn't have Nastrini, the White Sox No. 8 prospect per MLB Pipeline, on the mound.

“All right, 3-2 count, bottom of the ninth, World Series, bases loaded, down three,” said a smiling Nastrini, illustrating the childhood scenario leading to his eventual walk-off grand slam. “That was kind of the mentality growing up.

“Being a pitcher, it’s a lot of fun. I dreamed about it my whole life. If it happens at the end of spring, I break with the team, then that’s going to be awesome. But if I get the chance in the middle of the season or sometime during it, then that’s going to be awesome, too.”

That chance to pitch in the big leagues might come sooner than expected for Nastrini, who's currently in his first Major League Spring Training.

Nastrini threw four scoreless innings during a 3-3 tie with Oakland at Hohokam Stadium on Sunday, dropping his ERA to 0.82 over 11 innings with 11 strikeouts to four walks. The Cactus League numbers don’t mean nearly as much as the fact Nastrini pitches as if he belongs, showing that he won’t be afraid of the big crowds and bright lights of the regular season.

In the fourth inning, with Nastrini admittedly not featuring his best stuff, the A’s put runners on first and second via Seth Brown’s leadoff walk and JJ Bleday’s one-out single. J.D. Davis’ ground out then advanced runners to second and third with two outs. Nastrini fell behind to Ryan Noda, 3-0, but ended the inning on a ground out. Nastrini pumped his fist as he left the mound, but having this sort of composure in tough situations was something he had to develop.

“That was one thing I worked on a bunch with the Dodgers: Not letting those kinds of innings turn into really big innings, innings that hurt the momentum of a club,” Nastrini said. “Honestly very thankful for that experience in the Minors being able to do that because coming out of college, that was a problem that I had had.

“[I would go] out there and lose it a little bit, and I would let two, three, four runs score. So going out there and the first time really facing adversity in a game so far this spring [in the fourth], being able to have my composure and go out there and make pitches when I had to, that’s a big confidence boost.”

So, where does Nastrini stand with likely one start remaining in 2024 Cactus League action? For starters, the White Sox rotation is a bit confusing.

Dylan Cease was set to make his second straight Opening Day start, but he was traded to San Diego Wednesday. That five-player deal leaves Erick Fedde and Michael Soroka as the main candidates for that Day 1 honor, although Garrett Crochet and his dominant performance in the Cactus League after transitioning from relieving to starting would be the most compelling Opening Day nod.

“I think I know,” said White Sox manager Pedro Grifol with a wry smile when quizzed by the media pregame. “But you don’t know.”

It’s not even a certainty that Crochet breaks camp as part of the rotation given that the White Sox want to be very mindful of how many innings he throws in 2024. Chris Flexen figures to be part of the five, but as Grifol pointed out Sunday, the White Sox won’t need a fifth starter until April 6 at the Royals.

So, that fifth starter could open as a long reliever. It could be Crochet. It could be Chad Kuhl or Jake Woodford, two non-roster invites with a chance to make this team. It could be Nastrini, who came over from the Dodgers at the 2023 Trade Deadline with reliever Jordan Leasure, who could also start the 2024 campaign with Chicago.

“Coming into the spring I was like, ‘All right, I’m going to get to know the guys on the team, familiarize myself with the staff, Pedro, [pitching coach] Ethan [Katz],’” Nastrini said. “ I definitely didn’t think that was an option going into Opening Day, but whatever happens, happens.”