Hagen Smith is fine-tuning his mechanics in the Arizona Fall League.

The Chicago White Sox prospect displayed some of his progress Tuesday while pitching for the Glendale Desert Dogs against the Peoria Javelinas. He struck out Seattle Mariners prospect Jonny Farmelo with a 97.5 mph fastball to end a 1-2-3 first inning. He then struck out the side in his second — and final — inning of work.

“I knew I was going to be two innings, so just try to go out and attack the zone,” Smith said during a videoconference call Thursday. “I felt like I got ahead early, which is the plan. And everything went good from there.”

Outings like Tuesday’s have helped the left-hander earn a spot on the AFL’s American League roster for the Fall Stars Game, which will be held Sunday at Sloan Park in Mesa, Ariz.

Smith and infielder Sam Antonacci will represent the Sox.

“It’s awesome to get picked for that, playing with the best guys out here,” Smith said. “It’s been fun to watch everybody play, especially on the American League side.

“I get to talk with the people on my team and just chat it up and watch some good baseball.”

3 takeaways from the Chicago White Sox’s 2025 season, including 102 losses and those 1-run defeats

Smith, the No. 5 pick in the 2024 draft out of Arkansas, has a 2.57 ERA in five starts this fall for the Desert Dogs. He has 21 strikeouts and six walks in 14 innings.

“Just kind of making sure it’s little (mechanical) tweaks here and there — focused on doing what I’ve been doing right now, slow and smooth down the mound,” Smith said.

“And I think for me the big thing was trying to throw a lot of changeups against good hitters, see how it is. It’s come along really good, actually. Just keep throwing it and see how it does.”

The work continues for Smith, 22, after he went 3-3 with a 3.57 ERA and 108 strikeouts in 20 starts in 2025 for Double-A Birmingham.

“I thought my year was just all right,” Smith said. “Definitely went through some ups and downs, but I think failing helped me a lot to improve.”

Smith, ranked the No. 5 prospect in the Sox organization by MLB.com, missed a portion of the season because of left elbow soreness. He also spent time away making mechanical adjustments.

“After the injury, just kind of taking a step back and looking at what I was doing wrong and what I wasn’t doing,” Smith said. “Just coming back from that, I felt honestly really really good every single week.

“When I feel good mechanically, it frees up my mind to be able to attack the zone and trust my stuff.”

Tuesday’s start served as one of those examples.

“I think he’s come along real well — especially just the last outing, it was kind of like ‘whoa,’” Antonacci said of Smith during a videoconference call Friday. The pair were also teammates on the Birmingham squad that captured the Southern League title.

“He’s really even-keeled, very humble and I’m proud to call him a teammate because I sure as hell wouldn’t want to face him,” Antonacci said. “I hope to play on the infield behind for a very long time.”

Antonacci, 22, has mostly played second base this fall. He entered Friday slashing .379/.506/.515 with two home runs, 13 RBIs, 20 runs and nine stolen bases in 17 AFL games.

“I don’t really want to be known as a good Fall League player, I want to be known as a productive big leaguer that brings a championship here to Chicago,” Antonacci said. “There’s still a lot of work to be done to get to where I want to be.”

It has been an extension from the regular season for the 2024 fifth-round pick.

Antonacci, the No. 11 prospect in the Sox system according to MLB.com, had a combined .291/.433/.409 slash line with 21 doubles, five home runs, 57 RBIs, 78 runs and 48 stolen bases in 116 games for the Arizona Rookie League Sox (three games), Class A Winston-Salem (64 games) and Birmingham (49 games).

“I know there’s still a lot of flaws that I have and a lot of stuff that needs to be worked on if I want to get to where I want to be some day,” Antonacci said. “That’s what the offseason is for, big offseason coming up. A lot of room to grow.”

While it’s natural to think ahead to next spring, the two are concentrating on finishing the Arizona Fall League on a good note.

“I’ve still got one more outing, potentially two here,” Smith said. “So that’s what I’m looking at right now. I don’t really have any expectations (for the spring of 2026), just come in, be ready. I can only control how I throw, so that’s really all I’m focused on.”