MIAMI -- Fernando Tatis Jr. makes it look so easy. Chris Paddack, too.

But for a young ballplayer arriving in the Major Leagues, the transition is never easy. In some cases, it can be brutally difficult. On a disheartening night for the Padres, it’s worth pausing to remember that.

Two San Diego rookies struggled on Tuesday in a series-opening 12-7 loss to Miami at Marlins Park. Left-hander Logan Allen allowed seven runs and didn’t finish the third inning. Right fielder Josh Naylor misplayed a line drive and bounced into a double play in a big spot.

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With the loss, the Padres fell four games below .500 (45-49) for the first time this season. They’ve bounced back from a few losing streaks already. But after dropping four straight games to open the second half, there’s a looming sense that the season might be slipping away.

“We've got to go out and win these games and win them consistently,” said Padres manager Andy Green, whose team has dropped three straight against the last-place Marlins. “It's a painful hole to have dug.”

That’s the most pressing issue. The Padres need wins to creep back into the National League Wild Card picture. When a couple of 22-year-old rookies falter in a winnable ballgame, those struggles are particularly glaring.

In the first inning Tuesday night, Allen put two men aboard with one out. He couldn’t locate his fastball, so he decided to start Marlins cleanup man Brian Anderson with a slider. The pitch hung, and Anderson crushed it 440 feet.

“They hit mistakes,” Allen said afterward. “You get away with that in the Minor Leagues. You get away with throwing a get-me-over slider when you're falling behind in the count. You don't get away with that here.”

The Padres stormed right back and tied the game at 3. But Allen coughed up four runs in the bottom half of the second. His fastball command was nonexistent. His breaking pitches were too predictable and, thus, too hittable.

It didn’t help that with the bases loaded and one out, Naylor raced inward on a Harold Ramirez line drive. The ball sailed over his head, and that gave the Marlins a two-run lead. They’d double that advantage on Garrett Cooper’s ensuing single.

“He was missing by quite a bit,” Green said of Allen. “... And when he got it in the strike zone, it was in a spot he didn't want it to be in.”

It’s worth wondering when Allen might start again for the Padres. Eric Lauer, who opened the second half on the bereavement list, is expected to pitch against the Cubs this weekend. That might make Allen the sixth starter on the roster.

Since his brilliant debut, Allen has a 10.54 ERA in four outings. The Padres have used a six-man rotation at times this season to limit the workload on some of their young starters, but that probably isn’t necessary right now, given Monday’s off-day.

Naylor, meanwhile, seemingly has more job security than Allen. But he would clearly benefit from regular reps in the outfield. Naylor’s sporadic playing time might also be impacting his performance at the plate, where his OPS dipped to .621 on Tuesday. When Travis Jankowski returns, it’s unclear how Naylor will fit into the outfield mix.

But that’s the short-term view. Naylor still projects as a long-term OBP machine with plenty of pop. Allen projects as a fiery lefty with a four-pitch mix. They’re not the first 22-year-olds to struggle early in their careers, and they won’t be the last. Plenty of those struggling youngsters have gone on to have long and successful careers.

“There's no particular path,” Green said. “It's an incredibly hard game at a hard level. There's going to be mistakes.

“We believe in the guys we have here. We believe in their future. We believe they're going to be a big part of what we do. At some point, you allow them to grow through it and give them some opportunities. Both those guys, [Allen] and Josh, they're going to be really good for us.”

The growing pains are, by definition, painful right now. But the Padres certainly aren’t writing off two talented young pieces based on a few rough weeks.