SAN DIEGO -- The kids are growing up so fast.

When the Padres promoted Logan Allen on Tuesday afternoon, he became the sixth top-100 prospect to suit up in San Diego this season. Like the rest of them, Allen’s arrival inspired talk of the team’s bright future.

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Then he pitched. And, yeah, that future sure seems bright.

Allen tossed seven scoreless frames, allowing only three hits, as the Padres rolled to a 4-1 victory over Milwaukee. Francisco Mejia hit a two-run homer to right-center. Fernando Tatis Jr. dazzled defensively. All three are rookies, expected to impact the big league club for years to come.

“Couldn’t draw it up any better than that,” said the 22-year-old left-hander.

Feeding of his adrenaline, Allen’s fastball played in the mid-90s during the first couple of innings. It dipped to the low-90s later in the start, but he spotted it perfectly. His changeup, meanwhile, was particularly effective. He threw it 16 times and recorded five swings and misses.

“We just couldn’t figure him out,” said Brewers center fielder Lorenzo Cain. “When we did figure him out, he was able to get the pitch he needed to get out of innings. He did a great job, had a cutter going, pretty good changeup, back-foot slider to righties. He mixed up his pitches really well.”

Mejia caught each of Allen’s last four starts at Triple-A El Paso before his promotion on Monday. The two didn’t miss a beat in the big leagues.

“I'd caught him in the Minor Leagues,” Mejia said. “But tonight was the night he had his pitches working the best. Everything showed up."

The Padres acquired Allen four years ago in the deal that sent Craig Kimbrel to Boston. Of the four prospects they landed in the deal, Allen was the last to make the big leagues. But he might end up being the best.

What’s next for Allen? That remains to be seen. The Padres have three off-days before returning home next Friday. They’ve shuttled pitchers back and forth between the Majors and Minors all year based on their off-days. But Allen’s brilliant debut might have earned him another start. Manager Andy Green seemed to indicate as much after the game.

Of course, that’s a question for another day. Allen spent Tuesday soaking in the atmosphere. At one point during pitchers’ batting practice he found himself disconcertingly calm.

“I looked at Eric Lauer, and I said, ‘Am I crazy? I’m not that nervous right now,'” Allen said. “He said, ‘Oh, you’ll get there.’”

Lauer was right.

“I start strapping the pants on, and it was like: 'Oh, this is real, this is happening,'” Allen said. “The nerves were there. But sometimes it’s a good thing, keeps you human.”

Allen’s emotions took over in a big way, as he finished warming up in the left-center-field bullpen. A fan handed bullpen coach Doug Bochtler a pin with a picture of Allen and his older brother Philip. Bochtler passed it along to Allen.

The entire Allen family was on hand Tuesday, save for his older brother, Philip, who, at a young age, had a seizure and slipped into a coma. He woke 15 months later, in a condition that’s best described as a severe case of cerebral palsy. Philip Allen can’t talk or walk, and he requires round-the-clock care.

“That really brought the emotions up,” Allen said of the pin. “... I’d love to see Philip, wish he was here.”

Philip watched the game with his nurses from across the country in Allen’s native North Carolina. And his younger brother turned in a performance for the ages. Allen joined Jimmy Jones and Ricky Bones as the only pitchers in Padres history with seven innings and three hits or fewer in his debut.

The highlight of Allen’s night came in the top of the seventh inning. He faced three hitters, striking out Yasmani Grandal with a fastball, Travis Shaw with a slider and Hernan Perez with a changeup.

When Allen whiffed Perez to end his night, he spun on the mound, let loose a roar and pumped his fist. John Cena, the professional wrestler and actor who has developed a close personal relationship with Allen over the past few years, offered a standing ovation from the terrace level. On Wednesday, Cena will pay up on a longstanding bet that dates back to Allen’s teenage years. Allen once bet Cena $1 that he’d make the big leagues.

As Allen strode toward the home dugout, the rest of Petco Park joined Cena in its thunderous applause. Two innings later, the Padres were back to .500.

Yet another bright-eyed rookie led the way.