ATLANTA -- The Padres will begin another chapter in their youth movement on Wednesday night.

That's when right-hander Cal Quantrill the team's No. 12 prospect and 2016 first-round Draft pick, will make his big league debut. To make room on the roster for Quantrill, the club optioned right-hander Phil Maton to Triple-A El Paso and transferred righty Miguel Diaz to the 60-day injured list.

“It's a dream come true,” said Quantrill, who joined the club Tuesday. “I know, in relative terms, I didn't spend all that long in the Minors. But it feels like I've been waiting forever for this, so I'm excited to be here.”

It's unclear how long Quantrill's stay in the big leagues might last. His presence gives the Padres a temporary six-man rotation, as they continue to monitor the workloads of a handful of their young starting pitchers. Earlier this season, Pedro Avila was promoted for the same purpose, and he was optioned after just one start.

The Padres have the youngest group of starters in the Majors. Matt Strahm and Chris Paddack are on strict innings limits, and they have pitched with a minimum of five-days rest all season. Quantrill's promotion ensures that plan will continue -- even with the Padres in the midst of a stretch with 13 games in 13 days. Strahm will have his start bumped back to Thursday.

“What we’ve seen so far in the first month of the season is the plan that we talked about when we got to the end of Spring Training,” said Padres general manager A.J. Preller. “We’re going to be careful and cautious with the group, and we’ll incorporate as many guys as we can to help us be competitive.”

Quantrill owns a 4.68 ERA in five starts for Triple-A El Paso this season. Those numbers don't exactly tell the whole story. He was lit up for eight runs in his season debut. Since then, Quantrill owns a 2.86 ERA with a strikeout per inning.

The son of former big leaguer Paul Quantrill, Cal was selected by the Padres with the eighth overall pick in the 2016 MLB Draft. He was coming off Tommy John surgery at the time, and he faced a turbulent road through the Minors, as well.

After a rough start to his 2018 season, Quantrill found a groove during the second half last year. He barely missed out on a rotation spot in camp, floundering in his final spring appearance, then in his first Triple-A start. But the 24-year-old right-hander bounced back, and now he's headed to the big leagues.

“I feel like I took a big step at the end of last year,” Quantrill said. “I had a tough one to end spring, but it really feels like that was just a little blip in the radar. Stuff feels better, arm feels better, I feel stronger. ... It's just really starting to come together.”

The Padres will almost certainly option one of their nine relievers prior to Wednesday’s game to clear space for Quantrill. They expect to make another move Thursday to avoid carrying a three-man bench.

It’s possible that Quantrill’s first big league stint lasts as long as Avila’s: one day. But the circumstances here are slightly different. The Padres still have seven games in seven days after Quantrill’s debut, so there might be a benefit to keeping him on board.

“We’ve been very vigilant in making sure we take care of several guys in our rotation,” Padres manager Andy Green said. “… Cal’s going to start tomorrow, and he’s going to enable that to continue.

“But for Cal, it’s a chance to show he’s another one of those guys in a long line of starting pitchers that have shown up and done a great job for us. We’re all excited to see him tomorrow.”