PEORIA, Ariz. -- If there were any lingering doubts regarding Jackson Merrill's status on the Padres' Opening Day roster, he answered that question with one emphatic swing on Tuesday afternoon.

D-backs starter Zac Gallen threw an 0-1 fastball on the outer half of the plate. Merrill, San Diego's No. 2 prospect, put a smooth left-handed swing on the pitch and drove it to the opposite field for his second Cactus League home run in as many games, this one against one of the best pitchers in the sport.

After the game -- a 2-2 tie between the Padres and D-backs -- San Diego manager Mike Shildt wouldn't go so far as to name Merrill the Opening Day center fielder. But he said, "Jackson Merrill is going to Korea," and left it at that with a wry smile.

The Padres are just over a week away from opening their season against the Dodgers in Seoul. Merrill's presence on that flight almost certainly means he's bound for a roster spot and a starting role. Otherwise, he'd be staying behind at Minors camp.

Shildt again played coy.

"He's earned his way on the plane," Shildt said. "He's earned what's coming after the plane."

So what, exactly, is coming after the plane? The 20-year-old former first-round pick is almost certainly bound to become the youngest Opening Day center fielder in Padres history. He'll join Andruw Jones and Ken Griffey Jr. as the only players in the last 50 years to start Opening Day in center field before turning 21. (Milwaukee's Jackson Chourio could soon join that mix as well.)

All that for a career shortstop who had never played a game in center until a few weeks ago.

Merrill has held his own defensively. There will be growing pains, and he acknowledges that. But he's been solid enough, and the Padres' center-field options have been thin since they traded Trent Grisham to the Yankees in December.

More than anything, the Padres want Merrill's bat in the lineup. This spring, they ensured he faced as much big league-caliber pitching as possible. (He'd only ever played 46 games above A-ball.) In 12 Cactus League games, Merrill has posted a .343/.395/.600 slash line.

"I think [spring] has gone very well," Merrill said. "I think I've shown a lot of development over the past couple years. But I especially think that this team is ready to go. I think everybody in here is ready to go compete all year."

Merrill appears destined to be the latest in a line of prospects to be promoted quickly to the big leagues under Padres general manager A.J. Preller. Preller did the same with Fernando Tatis Jr. and C.J. Abrams, among others. When asked about his prospects' roster chances at the start of camp, Preller noted, "We're looking for players to come in here and just take the job and make it pretty clear that they're the best option for us."

Merrill has done precisely that.

Tuesday offered the latest evidence ¨C an opposite-field home run off an All-Star and the third-place finisher in the NL Cy Young race.

"I'm not being self-centered, but that's what I should do," Merrill said. "I should have a good AB, be ready to swing, be ready to hit.

"He came at me with a fastball, and I was ready to go. I'm not going to talk anything bad on his name. He's a great pitcher. But I was ready to go at that point."

Evidently, he's also ready to go halfway across the world for his big league debut.

"He's done a great job," Shildt said. "Couldn't be happier for him. Clearly, he's swung the bat well, played good defense, ran the bases well. He plays with a lot of heart, energy, passion. Plays smart. There's just a lot to like about Jackson Merrill."